Help identify my engine!!!

I just bought an '88 Prelude si, and the guy said that it is on its second engine. I am worried that this engine may not be the si's B20A5 engine, because there is no inscription on the engine itself. However, it does have the fuel injecter that only comes with the si, and not the s. Any help identifying the engine would be greatly appreciated. Thanks.
-NSXN8

the motor should... right next to the exh manifold or so, say b20a5... right by where the plug is at in the trans... it's a flat spot, and should be easy to read.

That helped a lot, thanks. Now i have a new problem, it just says b20a; now just what is that suppose to mean? There isn't a 5 after the 'a'. I wonder if they just forgot to put the 5 on, because as far as i know, there is no such thing as a Honda b20a engine!!!!

Its the right one dont worry.

i'm pretty sure the cars with numbers after the letter are usdm, while the jdm motors don't have a number...

hence the b20a.

or usdm b20a5...