Where were the masters set on the Peavey? Not all amps react the same with a tube change and also depending on how little they designed the power section to impart tone eg. overdriving the P.I. If you play predominantly amps that are preamp based for high gain, tube changes won’t make much of a difference.
I can definitely say the MKV I had for many years sounded quite different with 34’s. Even more so when turned up to a healthy volume. Really changed the top end of the gainier settings and reduced lows and highs of the cleanest settings. The difference in punch and attack between 45 and 90 watt settings also translated to recordings.
The differences I get between the 5 watt setting and 15/30 on my LSS are also significant in top end responses and midrange saturation. All these differences definitely picked up on close micing.
Ultimately….it depends.
I also agree with you as there are a few amps I have where, even though you certainly feel a difference, changes like bold/spongy tube vs S.S. rec don’t necessarily translate to a close mic recording. IME, These changes tend to be more noticeable with clean and medium gain settings rather than metal/hardcore levels of gain. It would be interesting to hear the Peavey set to a medium, crunchy gain and turned up a fair bit in a tube comparison.