Although the difference between a deluxe and ultramark is only in the grade of the wood, I have had several Mrk deluxe rifles that clearly had a lesser grade wood but I presently own a 340 Mrk V deluxe with wood that appears to be equal to my 300 ultramark. If there is a difference, it is not obvious to me. Obviously, there is a fine line in the grade of the wood is some instances.
My understanding is that weatherby produces a limited number of ultramarks each year in 257 and 300 as part of their normal production due to demand and those are available through retailers or distributors, but if you want a different caliber, you have to make a special order through the custom shop. I have noticed that Sports South has had ultramarks in 257 and 300 in stock in the past, so any dealer who purchases through Sports South could call up and purchase an ultramark that was produced by weatherby as part of its normal production runs. I would assume that one would otherwise be required to make a special order through the custom shop.
You can also purchase certain DGRs even with desert camo and teflon coating in the same manner even though they are clearly listed as custom rifles through the custom shop. Apparently weatherby produces a limited number of these rifles each year which are distributed through authorized distributors. I noted tonight that Sports South has 5 DGRs in stock including a 375 H&H, 416 REM, 458 Win, 458 Lott, and 460 wby. The price of one of these special production rifles is likely less than a special order through the custom shop.
I know that I was able to purchase a 416 DGR in desert camo with teflon through my local dealer who called his distributor looking a deluxe model. I immediately jumped on it because it was in stock and shipped and delivered in 3 days at a price much less then the same rifle ordered through the custom shop.
Just my experience.