First order of 'bidniz' would be to measure a pair of the GS bars you're interested in.
Note the center section width, amount of rise, pull back distance and the overall width of the GS bar. Naturally, you'll need 22mm bars or else the throttle tube will not fit/rotate.
The low euro-style R65 bars are outfitted with short cables. Longer R65 cables are available for throttle and clutch. You will also need a longer hydraulic brake line.
Some R65s were sold with the 'western' bars option which were kinda popular in the USofA. Higher for a more upright seating position. The wiring leads are just barely long enough to fit the R65 low bars so I would expect some extensive harness work would be needed. That or purchase the harness portions for the higher bars; if they are still available.