Need help w/ possible mis match heads

So last week I found out while replacing a head gasket on my ‘95 w/ 5.0 that one of the heads (GT40P) was cracked. Been looking into options to replace them because I can’t pull off a set of $1000 plus heads right now. Have had several people offer to ship me direct replacements which is where I may end up, but I found a set of heads that might be a nice upgrade but have a question about them.

Found a set of Edlebrock Performer RPM heads but it seems to not be an exact matched set. I’m including pics below. Overall they look the same but the bottoms have slight differences. In the description it says that the heads are “from different molds but have the same casting numbers”. I was told the slots in the bottoms are called “steam holes” or something. Can these two heads be used on the same engine or no? I’m not running a high HP setup. Basically stock with very mild cam (unless I upgrade), exhaust and cold air intake. If the slots are a problem, can they be machined in or would than not be financially worthwhile? Guy is asking $475. Has a set of nice 1.72 rockers but to be honest my knowledge of head tech isn’t good and I’m not sure if those will work or not. I’ll copy and paste specs that were listed below. Sorry if pics posted weird, posted from iPad... Thanks!

This was ad...
“Edelbrock performer rpm bare heads for ford 302/351. They have 190cc intake runners made for 2.020 intake and 1.60 exhaust valves. Heads came from different molds but have same casting numbers as you can see from pictures. Everything is the same. I will throw in a set of 1.72 rocker with heads.”
 

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Definitely odd one of them must be a newer design. As long as the combustion chambers are the same size I would think it would be fine to run them.
 
Those heads, even if they are ok to use together are bare. Have you checked the price to fill them with valves, springs, retainers, keepers? That stuff adds up.

On closer look, those combustion chambers look different. If they came from different places, how would you know if either or both had been milled. And if so, how much? Lots a ways to go wrong here. I think I'd keep looking
 
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