Are we talking about a Romberg bevel, the sharp cut put under the low strings of cellos and basses toward the end of the fingerboard? I’m no expert on this at all but garnering from at least a couple of recent conversations I’ve had, it seems that more and more folks are regarding them as a dated practice, at least on basses.
The last time I had my fingerboard dressed, it was done so that there is a little more clearance under the lower strings than the standard 1 mm difference between the height of each string at the end of the fingerboard, maybe an extra half a mm under the A and 1 mm or so under the E. The curve of the board was maintained and honestly it’s all but unnoticeable to me, besides having some extra dynamic range for loud bowed notes on the low strings before they run the risk of slapping the board.
My preference is for rounded, but if an older bass fell into my hands that I absolutely loved, and it had a bevel, I’d probably leave it as is unless the board was due for a replacement.