No, the LP comes from 1973, and Loma shut its doors in '69.
I have both issue and promo copies of Delilah Kennebreuw, but just the promo of The Soul Shakers. Would love an issue though... As for Larry Laster, I personally think that the issue is harder to find that the promo. I see Pat Brady has one up for auction at present, which shows that it's demand that keeps the price higher than it should be. I have two issues, so maybe that just proves I'm wrong on those being harder to locate. Either way, it's not a tough one to find.
Many of the promos are much easier to find than the issues. This is particularly true for the non-soul stuff. It's not easy to find issues of Limey & The Yanks (2059), the second Belfast Gipsies release (2060), The Poor (2062), Kim Fowley (2064), or Butch Engle & The Styx (2065).
As for Redd Foxx, he is far and away the most successful act to come out on Loma and had four out of the seven LP's the label put out. His LP's have been reissued umpteen times over the years, in later years on WB, such was their demand. Look on eBay and you'll see loads of copies, all going for a couple of quid.
I agree that WB probably did want to keep Redd Foxx at arms length, and that is why he came out on Loma. Bill Cosby was with WB at the time, and was very successful, so at first glance you would have thought it natural for Fox to be on the same label.