Western Electric 300B question

I recently bought a matched set of Western Electric 300B tubes from Doug's tubes, which is an authorized dealer according to the Western Electric website. According WE, tubes with no serial numbers are B stock and has not met the standards.

My tubes did not come with the serial numbers etched on the tube and the dealer told me that he got them from Penta Labs, a tube company that bought a bunch of the WE 300B tubes in bulk quantity. According to my tube dealer, Penta Labs tested the tubes and he did provide me the print out of the test results that tested OK.

My question is: Is there a sonic difference between the tubes with serial numbers VS tubes with no serial numbers?
Friend of mine bought WE 211 from Penta labs as well.....I wonder if his tubes were also B stock and like Spareribs, wonder about the quality issues.. $300 a pair seemed like a good deal.........or not likely?

Probably not but I can tell you from experience that they will likely develop problems over time. I had a set and they started to emit a popping sound after a short time. The tube was repleaced by the seller and the new one started popping too. Since you already own them I wish you luck but for my money I would never buy B stock tubes again.
I just emailed another tube dealer at Allegrosound.com who sells both WE 300B tubes with and without serial numbers. The ones with no serial numbers are cheaper. According to Rick at Allegrosound.com, there are no sonic differences.

My feeling is that the tubes with no serial numbers were not tested by WE but if they were tested by another company and tests OK, I assume the tubes are fine.

But it's just my guess. I think WE sold a bunch of non serial numbered tubes for economical reasons, which would be fine as long as most of them are legitimate.

Again, this is just my educated guess.