Instruction: Answer the given question using the supporting document.

Input:
Question: Are these P 51's marked "US SHELBY CO"
Document: Well what can you say about a can opener? A lot, as it turns out.The main reason I decided to write this review is because the lead review thoroughly dissed this item, and that was not my experience. Some clarification is needed here.He obviously got a different product, probably an el cheapo copy, because mine worked perfectly. I did order mine from this same Amazon website listing, but the seller at the time was HobbyToolSupply.The P-51s I got are marked "US SHELBY CO", and these are indeed the genuine USGI can openers.
I have purchased these in July, 2012 and they are not marked "US SHELBY CO", in fact they are not marked at all. So I think they sell some fake Chinese garbage. They bend like aluminium foil. Stay away.
This may have the same shape and size as a Type P-51 can opener but it is not one. A real P-51 would be stamped "US SHELBY CO". The real ones work great and hold up very well. Knock offs... not so much.
These are the real deal. They are stamped " US SHELBY CO." which, as I understand it, make them authentic. They function as promised; a good addition to any survival bag.
Wikipedia says genuine USGI P-51s may also be marked "US MALLIN SHELBY O". The genuine P-38s have different markings. The Mallin Co. went out of business some time ago, and so it would appear that these are all from US military surplus (see Wikipedia article on "P-38 Can Opener").The P-51s work better than some of the hand-sized can openers that I've had the misfortune to buy from stores over the years (there's only one kind of those that really work and that I will buy nowadays - the one with the tightly meshed gears).I remember my dad using the smaller P-38 can opener when I was a kid, and I remember these were harder to use, which is why I got the P-51s.These can openers have a terrific military history behind them, worth reading if you have the time.For the present, I have been using them whenever I can't find my one and only good other can opener.
I don't really have anything to add to the other excellent reviews. I tried mine out on a can of creamed corn and worked like a charm. Of course, it was strange to use compared to regular openers. Don't wait to practice. I ordered mine in July 2012 from HobbyToolSupply and all 10 were stamped US SHELBY CO (AFAIK is authentic). Arrived fast too.
I ordered this pack and it arrived quickly, less then one week. The items were well packaged in a zip lock bag and enclosed with a bubble wrap envelope. I checked each one and all 10 are stamped US Shelby CO. These are the real deal, U.S. made, P-51 can openers, with a small hole to easily attach to a key chain, lanyard or other carrying device.I was easily able to open a can with it without issue. Note, they do not come with instructions, but it is not hard to figure out how to use them and you can find YouTube video's on it.I highly recommend these they are Awesome!
These arrived quickly and nicely bagged up. They are tried and true, Shelby P-51's.These will be great for our rucks and will even hook right in with our mess kits. They aren't the easiest to use but they get the job done better than a rock or a knife!
Those can openers bought from the dollar stores seem to always break after a while. But these can openers P-51's are very reliable.So easy to operate and easy to hide in your wallet. They dont take a lot of room, but can come in handy during sticky situations.Also, if you run out of ammo, you can probably melt these to make bullets for the zombie apocalypse.
The P-51 openers I got had no markings and the cutter's did not snap agianst the lever as previous openers I have owned. The notch that catches under the rim of the can to give leverage in cutting the top of the can  off does not hold very well. They work but not as well as P-51's I have owned before. With the less than average performance of these generic P-51's I got 3 stars is the best I can do.
Answer: NO!!  They are cheap Chinese knock-offs & not even in the plastic/poly bag.  This applies to ones sold by Allegheny Surplus Outlet Inc.  Tried to resolve this with them to no avail. I would have to eat shipping both ways.....