Depends what you mean with "professional".

It's very good quality thought. Nice mahogony shells.

If I'm not mistaken they came with die-cast hoops on all toms. So if you're planning on buying the picured set check out if the reso hoops are still there. If not, be prepared to spend extra bucks for buying replacements. Also ceck for in roundness of the bottom side of the shells, and the quality of the reso side bearing edges. There may be problems due to being used without reso head.

Looks like a 20" bass 16"x16" 14"x8" 12"x8" a pretty common early to mid 1970s set. These are Premier, just that, played by many professionals. There was only one range before Elites, Soundwave etc. Cheaper drums were badged Olympic, same shells but pressed hoops and weaker hardware. Don't worry about the catalogue set number as you could order whatever you wanted then, but this is actually a 303 (B303 had 22" bass)

Shells are African Mahogany (not cheaper lauan) with beech re-rings

Thank you all for the answers

Question: how can I check, without removing the heads, if the shells are pre-international? Are the diecast hoops synonym of pre-international sizes and the s hoops synonym of international?

By the way, I have a Premier (maybe Olympic) 16" floor tom that has an "International" stamp in the shell.

African mahogany shells won't be pre-int

It looks like the 70's kit my Uncle Lee had but with the bottom heads taken off.

At the moment I have many kits waiting for restoration but I am tempted to buy this one. The kit is completely for sale. I have a feeling that this will bring some good stuff attached to it, like cymbals, etc.

The sizes are a little bit odd for me, starting on the 14x8 tom (not usual) and ending on the 20" "small" bass drum, considering the tom sizes. On another hand maybe this is a Plus for collection purposes.

Would you buy it? :)