M20 swap

[slotsmd]

Just got an 87 E30 in rough shape, planning to run it in LeMons race. We are going to swap motors, bad compression on one cylinder of installed engine, and we got a spare engine in the deal. Trying to identify the engines to ensure the right ECUs but the engine numbers don't follow the numbering logic we've been able to find online. Each of the two engines just has a single, eight-digit string of numerals stamped into the boss down near the oil pan. First engine is 24496360. Second engine is 20766825. Pix attached. Any help identifying the engine type/year would be much appreciated.

[bangn]

Bmw stamp the year of manufacture on the head towards the front on the intake side. On the 2.5 i know they do

[dashboardmonkey]

First pic (red engine) is an "e" engine. I can tell by the non-toothed main crank pulley.

Can't tell on the other due to crank wheel not being in pic.