Other than bolt pattern, are they the same? Are the wires any different? I do know the plug is the same. First picture is from a 2006 Y8 EK and second picture is from a 90 civic EF.
I've searched the forums and there's mostly just posts about people having issues with their IACV.

 

The thru holes for the bolts are different dimensions apart.

also, there are both 2 and 3 wire iacvs, but the plugs look the same until you look at the prongs inside.

 

Oh damn. I didn't look inside. I just seen the plug fit and plugged it in. I'll check tomorrow morning.

 

If it plugs in, then it’s the same 2 or 3 wire.

but do the bolt holes line up?

 

A little bit of information since I left it out. The car is a 1990 civic STD hatchback with a D15b1, I did a MPFI swap and used a manifold off a d16y8
I'm mostly just curious if the two I posted in pictures above function the same since I've been dealing with idle surge issues when the car warms up. There's a million posts about idle surge I already know. Just trying to make sure they're the same and cover all the variables since I didn't have this issue before the swap.