4.3l head orientation

I'm rebuilding my motor on my 93 awd Astro. I had the heads cleaned and now I don't know which one is left or right. Does it matter which way to go on? Because they both look identical, and they fit on fine on either side. Is there any way to identify which one is left or right, thanks

Check the bolt holes for accessory mounting. You'll want those to the front. ;)