I'm bit confused by the cross-referencing between tubulars and tyres here.
I would generally assume 'tyres' means clinchers, whereas tubulars means tubs. Tyres/clinchers can't be used on tubular rims and vice versa.
But to answer the basic question: 23mm is pretty much the standard size for tubulars on road bikes so yes 23mm tubs would be absolutely fine on rims suited to tubular tyres.
Wider tubs are available, right up to things like 35mm cyclocross tubs. However, it's usually argued that tubs offer a bit better shock absorbtion and comfort than most clinchers, so even a fairly narrow 23mm tub would probably be a bit more comfortable than a 23mm clincher.
Also, given the lower risk of snakebite/pinch punctures, maybe it's possible in theory to use tubs at a slightly lower pressure - again, a bit more comfort (but I wouldn't want to guarantee it, I have tubs on a few of my bikes and generally try to keep them fully pumped up).
Have a look at the sticky on using tubular tyres at the top of the Road forum for some discussion of these kinds of issues.