I've got the same tuners on the '71 F30 I just got, and I did oil them minutely just at the pivot point and a touch on the gears with an extremely fine oiler, adjusted the tension as needed, high E and G are always the most worn tuners and they are a bit sloppy, but I strung it up with mediums, and I'd have to say the tuners, in Japanese fashion, are a joy to use, really smooth and stable.
If I was to compare them with vintage strip Klusons, which I actually like just fine, I'd say the Guild strip tuners are much smoother with improved gear ratio, they have a more precision feel.
Pretty surprising from what at first glance look like cheap strip tuners, looking so much like the garbage tuners on many cheap acoustics of the past, but upon closer inspection, you will see they they are nicely made, the little gears are very fine with excellent plating even after all this time, and they are quite stout.
Even the ferrules are quite tolerable, compared to some of the huge monstrosities they stuck on the headstocks a few years later...
I should post a pic of the open back Grovers on mine. I haven't seen them on another one. They're pretty cool looking and they feel really nice.
PS I've never thought they were anything but original on mine, looking at the back of the headstock, I'd have to say they've been on since day one, and they really are pretty neat, and light.