"Since 1961 Pacific Oil Cooler Service, Inc. has operated as F.A.A. Repair Station RF3R813L":
Pacific Oil Cooler Service
If they say it's good, it's good.
And clean/inspect/test doesn't cost silly money - not for the peace of mind.
Last used oil cooler I bought, had seller ship directly to them. Because it was going there anyway before it went on the car...