shop drawings are intended to detail the fabrication of the pipe.  Lengths, diameter, wall thickness, types of joints, strength / class etc. are shown by the manufacturer as interpreted from the plans.  Elevations of the installed pipe are unknown by the pipe fabricator and are only established by the contractor during installation.  these are sometimes recorded on the as-built plans

Are you refering to the pipe itself or the manhole and catch basin structures?

We regularly check shop drawings of the structures to ensure that the invert of the pipe openings, rim elevation, pipe angles, inclusion of sumps, or outlet structures match what was called out on the plans.  

Great, thanks cvg and bpattengale, that answers my question.  

(I meant to post earlier to say thanks.)

are we confusing the terms, "shop drawings" and "as-builts" here?  As cvg mentioned, my "shop drawings" don't have anything to do with the plan inverts...it's just a detail and specifications to which the manufacturer will build a specific item in his "shop."  As-builts are done in the field and updated with specific information as needed.  Sometimes I make the specs require as-built inverts and some not.  I have found this useful in some cases where we had to go back and determine what wasn't working with a particular site's drainage design.  I just created a model using the as-built inverts and was able to quickly pinpoint the problem.  I don't usually require inverts on the as-builts for smaller projects (with smaller construction budgets).