I thought it was generally dangerous to allow people to type 0123 in a GUI box that expects an "ordinary positive integer". For example, in the VLAN tag field you can enter things like "00002". I just tried it, and in this case it seems to work OK. In other places the string like this that is allowed into the config may be put into conf file or command line "--param 00002" and if the utility in question is a bit dumb, it may not like it. It seemed to me that there was no point allowing users to enter "00002" - may as well make them enter just "2" and not risk any downstream effect from unusual forms of expressing a positive integer.
Anyway, whatever you think. It will be easier if you make the changes in the way you guys like to design it. If I try to guess what coding standard is acceptable it just becomes a back-and-forth guessing game. Please go ahead and make the changes to achieve this validation in whatever way you wish.