As a current UTV owner/user/supporter... I certainly hope so. (Finding good "spare" systems/parts is and will be important for those interested in continuing to use UTVs.) I'd suspect Hard Drive swaps might depend on the specific buyer(s). With a potential "rarity" of PATA/IDE Hard Drives at local stores... it might be a nice selling point if you'd offer the option. Also, depending on the buyer's ability to download the software... if you can install the OS 3.8 for them... It could also be a selling point.
With that said DirecTV isn't going to make it easy for "new" owners/users to jump on the UTV bandwagon.
Officially, they'll want to only "re-activate" UTVs that are activated by their "original" owners (Meaning eBay'd UTVs aren't suppose to be able to get a fresh card and be activated by a "newbie" or even an existing customer even if they've got UTV service).
But, there is a "grey" area where existing UTV users could "swap" cards from an existing "active" UTV into a "de-activated" UTV (thereby activating service on it) and use it that way. (With DirecTV none the wiser.)
(Requires the account holder to "refresh" their access Card via their On-Line Account... maybe via Auto-Phone Support... or even Customer Service)
Since UTVs usually require this kind of "refresh" anyway to quickly regain Local Channels after a Hard Drive/OS Install or "Factory Restore"... it's easy enough to get DirecTV to do this without question.
If you check eBay rules they do outline the current DirecTV policy to not active "Non-Rid" Receivers (like UTV and earlier receivers are) and how these "Non-Rid" units aren't suppose to even be "compatible" any longer. While that isn't really true... DirecTV's policy is basically supporting a phase out of Non-Rids. So while this "grey" option will probably still be around for sometime... allowing say the owner/user of an old Sony B2 DirecTV Receiver to go out and buy a replacement B2 or other compatible Non-Rid receiver and "swap" cards... that market is probably limited (and dwindling more with time).
Many Customers will likely call DirecTV and be told "Sorry the UTV isn't available anymore... but we can send you out a XYZ Model DVR tonight you'll have it in a day or so... No charge, maybe a re-up on the contract/lease... all done." They'll probably take advantage of that and not look back.