Sup shredders,

I have a 72' telecaster deluxe from fender with the stock Fender® “Wide Range” Humbucking Pickup... I love the way it sounds now, however... I was thinking of replacing the bridge pickup with a gibson 500t pickup I have lying around for perhaps more gain/tone?

I play rhythm guitar in a "melodic hardcore" band...

Basically high gain stuff...

so let me know what you think, good idea to change pick ups? yay or nay?

72 Telecaster Deluxe
Triple XXX Halfstack
Boss Noise Supp.
Boss Tuner Pedal.
Shure PGX14 Wireless
Well, basicly, a pickup's a pickup, so if it has humbuckers to begin with, it'll probably be fine... but, if you like how it sounds now, then for dear God don't change it, but follow the golden rule, "If it isn't broken, don't fix it".

Guitars: Ibanez SV5470F, Ibanez Xpt700, Fender MIM Standard Stratocaster ('04-'05), Jackson Ps-2
Ashton AG200,
Amps: ENGL E530, Bugera 6262-212,
FX: TC Electronics G-major 2, Behringer EQ700, Morley Volume / Wah
It might give you a heavier sound, but if you love the way the stock pickup sounds, you should stick with it. I also don't know if that Gibson humbucker would be a direct replacement for a Fender humbucker. The dimensions might be different enough to require some modification.
Fender Wide Range replicas are bigger than most normal humbuckers, and Gibson pickups have smaller spaces between strings than Fender ones do.
Some Fender humbuckers use 250k or 300k pots in them, so if you want to change them make sure you get 500k pots.
I'd go for it. PU replacement is such a simple task which will tale all of a few minutes. The tonal possibilities, no matter how slight, will always be good to discover. Prepare to change some of your settings, etc. to account for the changes.

I think you'll find that the gibson pickup is too small to fit in the wide-range spot.