You can lube a plate-mounted stabilizer, but there's no point in clipping and band-aid modding, because those things are done to dampen the impact of the stabilizer sliders as they hit the PCB, and the sliders don't hit the PCB with plate-mounted stabilzers. Also, spacebars are louder with plate-mounted stabilizers because the sound of the spacebar bottoming-out transfers though the metal plate, as opposed to the fiberglass PCB which dampens the sound more. So, yes, a lubed plate-mounted stabilzer will be better than a non-lubed one, but it will still be louder than the PCB-mounted equivalent. Finally, the bottom-out sound will be deeper toned with the PCB-mounted stabs, again, because of the PCB material. The difference is like using switches with a metal plate vs. an FR4 plate (which is the same material as PCBs).
Of course, as I said, everyone is free to like whatever pleases them, and there's really no such thing as 'better' or 'worse'. On the other hand, a majority of people in the hobby, myself included, prefer the deeper 'thock' that comes from PCB mount. Personally, I don't use GMK/Cherry stabilzers anymore (since retooling has screwed them up pretty bad), so I don't have to worry about clipping anymore (using Durock stabilizers), and I used to electrical-tape-mod Cherry stabs, but don't anymore, since I really enjoy the deep 'thock' of a properly-tuned stabilizer without the band-aid/tape modding. For reference, if you haven't watched Nathan Kim's videos, check out Taeha Types, and compare the sound of his builds to videos of keyboards with plate-mounted stabilizers. He doesn't cushion the bottoming-out of his stabs in any way, and they always sound really good. (I know he builds expensive keyboards, but the same principles apply to keyboards of any price).
I can't stress enough that I'm not trying to tell anyone what they should or shouldn't like. My point is simply that the same amount of tuning will not produce the same results with plate-mount as opposed to PCB-mount, though you're certainly free to like plate-mount if that's what you prefer. Personally, I've never been able to use a spacebar with a plate-mounted stab without putting a silent switch, or a Frankenswitch with a silent stem, under it. On the other hand, on the Klippe I'm typing on right now, I put a Halo stem in the switch underneath the spacebar, just to emphasize the satisfying 'thock'. But that's just me and my personal preference, that's all.
I'm just explaining this because it's very easy to spend a lot of money on keyboards based on assumptions that don't pan out when you build the thing after spending hundreds of dollars. Stabs, lubing, plate material, switch choice, keyboard design, etc., they all provide different effects, and endless combinations. The more you know going in, the less time and money you waste finding what you want, I think.
Long story short, you can get spacebars with plate-mounted stabilizers to sound decent, but it generally takes more work, and it will still sound different than a PCB-mount equivalent. No necessarily better or worse, but different... and it might be best to compare the differences in sound through videos, simply to determine your preferences before spending money. Whatever the case, enjoy your keyboards!