Ah, but it would appear he was looking the number up under exhaust pipes not manifolds. Under manifolds EPC lists nuts and studs but under exhaust pipes it only lists bolts, my 2.5 has studs/nuts on one manifold and bolts on the other.
So he didn't get it entirely wrong but could use a bit more time or common sense to look further on ECP and to be honest the first time i was asked for studs/nuts it took me a little longer than normal to find them.
Problem we have these days is we just don't have new blood coming into the parts trade, kids either want to be a Tech or Salesman, nobody ever thinks of the parts trade. The ones that do come for interviews are hopeless and have a job writing there own name in the correct box on the forms.
Also there is no training for parts, you can give someone an over view of EPC and how it works but you can't train someone to know where very part for every car is listed, i've been in VX parts for twenty five + years now and i sometimes still think where the hell have they listed this part, also doesn't help that different people including those in the trade have different names for different parts.
What we do now is if we take on someone who doesn't know much about cars then we kit them up and put them in the workshop to shadow a tech for a couple of weeks so at least they get an idea of what parts are and where they go, not sure if other dealers do this as well, also it can be a confidence thing about asking someone on the phone to give a better description of the part and its placing.
So at the end of the day he may have been daft or it may have been the idiot who wrote the EPC page and put the part in the wrong place as to why he's having a problem. Also with a car this old it could have been someone had mucked about with it and fitted studs in place of. The best one i had was a guy on the phone wanting a front skirt for his front bumper. The car was an LS model so it wasn't factory and how he described it i couldn't find anything like it. I asked him to pop in so i could have a look and when he did it wasn't even a GM part.
If anyone wants an internship (no pay) for a month to see what its like on the other side of the counter/phone then let me know

Andy