So, you need to look at where the spokes end on the curent build. The spoke end "target" is, typically, the bottom of the nipple screwdriver slot. The depth of the srewdriver slot is about 1mm below the end of the nipple. If the spoke ends reach the end of the nipple, or extend beyond it, on every spoke, you stand a good chance.

As already mentioned, ERD values that you find, even when published by the rim maker, may be different than what you may consider ideal. Also, with dished wheels, ideal spoke length will be different for each side so you may have different spoke end location for the drive and non-drive sides of a dished rear wheel, for example. So, check every spoke.