Parts of them arrived disassembled in containers (»crated«) and were assembled at the Plant #4 in Kolomna, Moscow region, and possibly at the Gorkiy Auto Zavod (»GAZ«).
The ingenious Russian designers eventually found a solution by combining the mobile BM-8-8 82mm rocket launcher with the notoriously passable »Willysov«.
As comtemporary photographies are virtually non-existent (at least afaik), it must be assumed that only very small numbers of MBs have been converted in that way.
Special thanks to Mr. Vladimir Shevchenko, Volgograd (!), for providing just the one photo it often takes to accomplish a drawing.