Hmmm.
Aside from the OP question, when doing a rebuild, I like the machine shop to have the pistons for the block, so that they can bore (or hone) to fit, but then the last several blocks that I've sent in have been for an overbore. (I have 0.5mm oversize pistons in my Supra, for example) The other set of pistons that I was considering were 0.1mm oversize, more of a "hone to fit" but given the condition of the used block that I picked up to send in to the machine shop, I opted for the larger pistons.
Even f I was going with a standard bore, I'd want the machine shop to have the pistons before it leaves the shop, so that they could all be checked for appropriate tolerances.
I'd probably be less picky if I were doing a rebuild to deal with stock power levels... Or maybe not.