Yamaha A-S1200 + KEF R3 Meta + KEF KC62 — Good Match?

Yes, the A - S1200 is a fine match. For the $3K+ you spent it better be! 

All amps of low noise, distortion and low output impedance will sound indistinguishable.

A Fosi V3 would suffice and save you a lot of money, though lacking the bragging rights of the A - S1200.

From the specs it looks good. I have owned a couple pairs of KEF speakers, which can be hard to drive, and the Yamaha should be able to handle them well. It will come down to whether you like the combination. Forewarning, if it is brand new, don’t jump to conclusions when you first hear it, give it a couple weeks of continuous play as it will take time to break in.

A vast majority of Audiophiles do NOT buy equipment for bragging rights. The few that still believe this outdated stereotype are usually DIY, vintage only, naysayers, a miser or just an overall negative unhappy person! Regarding the OP’s question, I would try an amplifier with more warmth/density and overall darker presentation. McIntosh, Electrocompaniet, Audia Flight, Norma Audio or even a less refined Hegel might prove a better match with KEF.

Thank you all for your responses. I sure do learn a lot from this forum. Hope to see more opinions/ comments. Thanks again!

@kevron99 I’ve had the Yamaha as1200 for just under a year and have been very happy with it. It’s driving a pair of 1982 Polk monitor 10a with updates. Excellent sound quality that improves with time. It replaced a vintage Yamaha integrated and sounds equal if not better. 
My only regret with the amp is not getting the 2200, it supposedly has the same preamp as the 3200 and uses thicker occ wire. I doubt it makes a huge difference though. Also the price puts you closer to a Luxman which may be better. But unless you live in Japan, the Yamaha is a great value.