If you own it you have every right to peel it. However to me that seems like a waste. If you want the btc sell the unpeeled thus preserving the physical bitcoin and you’ll certainly get a premium even if it’s come down compared to historical prices. Take the principal and buy bitcoin and now the new owner has a rare collectible and you have the bitcoin you wanted. Just my opinion.
As with most thinks it comes down to how soon you need the money and how urgently.
Example selling a Cas coin:
Auction assuming you don't want a fire sale price: 1 week
Payment/escrow/delivery: 1+ week
Confirmation of receipt and release of funds from escrow: 2 days
* Assuming no delays with mail, tracking, etc., which is certainly not a given and can easily add weeks for resolution. For example, if the mailman misplaces the shipment, you aren't getting your BTC from escrow for some time.
If you have a gilt/silver you'd prob give up 30-40% of face by peeling, but only 10% or so for brass. So ultimately it's just how you value the tradeoffs. It does pain me when people redeems a gilt/silver. The brass, not so much, especially when you consider all the hassle involved.