Of course. Colt would sell (and does sell) anything it makes. Colt needs to make more of what the market wants, but apparently cannot.I'm sure they'd sell every one.
AMT used castings on its 7-inch Longslide. No other clone maker uses 7-inch barrels and slides. I assume Colt would insist on a forged slide. Perhaps some of the 6-inch clones use forged slides, and they might contract with Colt for forged slides to finish, but I do not know. (I think a 7-inch Gold Cup would be needed to give the Colt something no one else offers. The demand for 6-inch clones is already being met. Colt would have to "share" that market and that market is not that big.) A billet slide might be an acceptable substitute for a forged slide. Of course, "modern" castings, such as those used by Ruger on almost everything, are perfectly serviceable if Colt would go that way. I suspect Ruger would produce castings for Colt, as it does for other makers inside and outside the firearms industry.Vendors already making long slides may not be able to do forgings to Colt standards if they do forgings at all. Some 1911 makers use castings rather than forgings.
I'd like to own a genuine long slide from Colt but I think the selling price would be prohibitive if Colt would do one.