Grey plate, so apparently not as valuable to collectors.
Will they sound better? Night and day mate. Not only will your wife hear the difference, but the neighbours will be banging on the woindows demanding to know what you've changed in the system. Random strangers will come up to you in the street to worship you, etc. etc.
Basically, the differences will be minute at best, in other words.
I've still got a few Telefunken ECC803S (and most of those a 'real' NOS). Widely reckoned to be the Holy Grail of ECC83 varieties. In a decently implemented circuit, most people would be hard pressed to tell them apart from a JJ Gold Pin. I sold a few to US collectors last year, so that's this year's holiday sorted.