Do I need to worry about the IV if I use a 32 byte random salt with SCrypt and AES-GCM?
If you use the key only once, then there is no danger of reusing a nonce with the same key because you're not even reusing the key!

A collision in the salt and password would lead to the same key, but though the probability of such a collision may be nonzero, it is nevertheless negligible for a 32-byte salt—unless, of course, you roll back your VM state and get the same initial RNG state, or equivalent.

Do make sure to use AES-256, by the way, and not AES-128, if you want a 128-bit security level.