The short answer is yes, but you’ll probably get a smaller cheque that way. If you have water damage, for instance, an adjuster can come and visually confirm which items have been damaged, and then you and the insurer can come to an agreement on the value of those items. With a fire or theft claim, that may be impossible. The adjuster will have to rely on what you told your broker when you last updated the policy, and perhaps a police report, to estimate your losses.
If you want the maximum payout after a loss, you should keep receipts, preferably not in the house itself (they won’t help you if the house burns down). You can even keep a video or photo inventory of your stuff. Remember that high-value items like jewellery, furs, cash and collectibles probably won’t be fully covered by a standard policy, even if you have receipts.