starrett telescoping gage repair

I have a set of Starrett telescoping gages that were in a tool box I scored at auction. (#S579H, set of six) One of the gages is missing pieces. The 2 1/8 - 3 1/2 gage is missing one of its 'anvils', and the spring. Is there any repairing to this gage? Are parts available, or can it be made...