whatever cap you install, it of course will not be the original. I don;t see how one brand of 2012 cap is somehow more vintage than some other 2012 cap. And i am sure there will be amp fans chiming in to report that so and so cap sounds more like the originals than some other brand. But that requires a real brand new 50 year old cap to compare to. As far as I know, no one makes 50 year old caps. And I'll bet my lunch money against anyone claiming to have ear memory of an amp from 50 years ago.
What matters to me is appearance though. I'd want caps in there that LOOK like they belong. Oh sure, that they perform well is a given. But those little rectangular things we see on pc boards look really out of place on an eyelet board, regardless of how they sound, for example. When I see giant film caps that look like they just escaped from some sort of speaker crossover, siting in a guitar amp, my first reaction isw "Oho, the cap snobs caught another patsy." To my eeye, those yellow axial Mallorys work just fine and look like they belong there. The new-age caps that are the size of a 12AX7 may sound terrific, but they look out of place... to me. WHen someone opens up an amp I worked on, I don't want their first reaction to be, "Oh someone has done a lot to this amp.' Like a plastic surgeon,, he doesn't want someone to remark, "Gee, what a great face lift."