Plenty available here in wide variety of depths. Would be surprised if there isn't a similar source in the US though.
Plenty of 3 bolt ones Richard, 4 Bolt "Brooklands" steering wheel ones are a bit thin on the ground. I agree with TimG, I would not trust it either. It's good idea for checking dimensions work but not to use. If you are tempted to use it then the stiff nuts are not in safety and it looks like a Traven quick release, so check it is refitted correctly.
