Well the best thing to do is take a couple pics of the proof marks and post them so they can be deciphered. I say that because 12,000 PSI seems like an awful light proof load. If it was proofed at 12,000 PSI then the working load would be approx 9,000 PSI or approx 620 bar. That would be a very very light load. If it is a 1,200 bar proof load that is actually about 17,404 PSI. Thus the easiest way to help in a safe manner would be some pics of the proof marks.

BB