OK, I know this is going to seem like I'm splitting hairs here, but I got real curious and just had to do some research. And, as a warning, this reply just might end up "book-like."
When I started working on vintage drums, it started from my love for the Pearl Fiberglass and Wood-Fiberglass lines of from the 70s. Like it or not, I do consider myself at least some-what of an expert on those lines. (Out of necessity and experience, I also have a deep love, respect, and knowledge of 60s/70s Ludwigs, but since this is Pearl thread we'll not go down that road here in this post.)
Since I've bought, traded for, refurbished/restored many Pearl drums and sets of the 70s, I've ended up handling a lot of Pearls from the 80s as well. And let me say this, Pearl, especially through the late 70s and throughout the 80s made a LOT of "evolutionary" changes as they tried to stay on the cutting edge of the industry. These "evolutionary" changes, if not kept in their proper perspective create a lot of confusion.
So, here are my observations concerning this set:
Based upon the overall hardware used on the drums (the tom arms, "Pearl" badges, BD claws and T-handles, these drums are out of the very early 1980s BEFORE Pearl started using the terms such as DX, DLX, BX, BLX, MX, MLX, etc. etc. etc. These drums are forerunners of these various lines.
The DX and DLX didn't show up in the US Market until 1983. It is my understanding the "D" actually was a reference to "deep" shells. The shells were made of birch and mahogany plies. The DX were wrapped, the DLX were lacquer finished. Also by this time you begin to see changes in the claws, t-handles, tom arms, etc. when you look at the catalogs.
Next up were the MX and MLX lines. The "M" stood for maple. They made their debut (again, I'm talking US market) in 1984. Still more changes occur in the hardware. The Pearl World Series line came in 1985, then the BLX didn't show up until 1987, and yes, the "B" stood for birch.
So, back to the set. At Fayray's description, the toms are deep shells. From the pictures we can see they're either maple or birch. But the badges are definately early 80s and the drum hardware is mostly carry-over from the style of the 70s.
BTW -- the most popular line of Pearl drums of all time, worldwide (based upon overall sales)? Their Export series, which these could well be. Exports also went through evolutionary changes, and included not only the cheaper "press-wood" shells, but also multi-ply maple and birch shells.
Honestly, I think I need to stick with the 70's FG and W-FG. They stayed much the same through most of their production periods.
Sorry (again) for another, long-winded rant.
Bill