I was briefly shown my son's WPPSI scores and they did a quick review of his areas of weakness. I would like to look at the test (if this is not verboten) and see what types of questions he missed. I didn't get a chance to write down what his areas of weakness were exactly, and I'd like to know so that we can work on those before he starts K in fall. Will the school let me look at the test itself, or is that closely guarded? Will I have to wait for overworked and understaffed gifted services office to get around to talking to me (I've been waiting over a month for an appointment)? Do they keep the test results in a file at his current school, or would that be kept in gifted services office still?

You won't be able to look at the test itself but the tester should explain what type of questions are in each section. Now, each SD is super different, some don't even do those individual tests. They should let you know what happens next.

Was it public school? If so you have the right to see anything in his file. You should be able to get a copy of his test results.

Agree: you won't be able to look at the test, but they should explain what the test revealed, and you can request a copy of the test results (do a web search for "FERPA request", and also see what's available under the law of your state).