Vlad I haven't seen every nor followed every thing on a what constitutes a warranty/service replacement/over the counter block or short engine BUt that engine being stamped G383 and the assembly date makes it , to me , a production line 2bbl block that for whatever reason didn't get a VIN put on it.

A warranty/service replacement/over the counter shouldn't/wouldn't have a model year stamped on it unless one was pulled from the production line to fill a warranty request ???