Good luck getting any satisfaction from eBay, particularly when it comes to misrepresentation of coins. I have reported dozens of obviously counterfeit coins and eBay never does anything. Not long ago an 1849 double eagle sold for over $4000 (!!!).
Is there a UPL? Or did you mean UDM which anacs used to use to reference a coin with mirrors deeper than dmpl. It stands for "Ultra Deep Mirror"
You are correct, as some time ago a Nigerian National sold me a prized date/grade Double Eagle, after increasing his feedback by selling small items. I promptly paid the funds, when by accident I found the auction image in another auction. I then realized he had immediately relisted the auction. I contacted eBay, who immediately removed all evidence that either of the auctions had ever existed. I never received any satisfaction from either the seller or eBay. I had a 2nd similar incidence with identical results, and others with vehicles. I've had incidents with Chinese SNAD products, and eBay stated that I'd need to return the product at my expense and PROVE that the seller received same in undamaged condition to receive a refund. The postmaster and I had a real laugh about eBays "buyer protection" plan. It's believed that the eBay buyer or seller protection plan is based on credible parties, which is seemingly becoming a tenuous environment on eBay (i.e. Caveat Emptor or Venditor) JMHO
In this hobby PL and DMPL are a hard thing to buy/sell. There's no reliable price guide for PL designated coins. Everyone thinks their coins are DMPL because they're shiney. Sorry but if it's not NGC or PCGS designated, then it's not PL or DMPL...period. A good idea is go keep a NGC or PCGS slabbed PL and DMPL coin handy to use as comparison when shopping for coins. There are many many coins currently in DMPL holders from all companies that would never grade the same way again if removed. This is one of those weird little corners of numismatics where it's easy to deceive and be deceived. One other quick observation...with common date Morgans, the PL designation really doesn't add much value at all. Each year and Mint has it's own idiosyncrasies so some years/mints are worth more than others but generally with common dates the PL doesn't mean anything at least in regards to value.
Even if you do know how to grade, if it's not certified as such, it's not marketable as PL or DMPL. The coin market is fickle, especially these days. Buying or selling raw coins like this is folly. It's one of the most misunderstood and abused areas of numismatics.
I agree that in today's market, it really needs to have the PL on the slab for it to count. On eBay there are a lot of coins being sold as PL that are straight up not PL or barely semi-PL. The photos need to be really good to know for sure, and it's a difficult thing to photograph. Having said that, there is a real grey area with semi-PL coins or lower grade uncirculated PL coins that have a lot of chatter or fogginess, where it will not get the PL if you submit it. I've submitted raw PL coins to NGC myself and had them come back without the designation, only to resubmit them for designation review and have them come back with PL, and it's happened several times. So if you really believe a coin is PL, you may have to submit it a couple times to get the designation.