Got it.... Ended up getting the 2gb model which is probably overkill for Punch Out!!, Super Punch Out!!, Arm Wrestling, Nintendo Playchoice-10 etc but I figured I'd get the middle model for other game / performance testing however this one is pretty much just going to be for those older Dual Screen Games.
First thing I was curious about since I place these inside cabinets without cases, is did they improve the design (from the rpi3b+) so I don't need to drill larger holes on the PCB... they did NOT... still need to drill holes the screws / for the common PCB feet screws don't fit unless drilling larger holes:
I also noticed this solder packet was incredibly close to the metal on the pcb screw, I needed to use a nylon spacer, which I've done in the past for the rpi3b+ however the rpi4 looks like I now need to use 3x spacers as opposed to 2x previously not a big deal.
Here you can see I got 3x heat sinks that came with it , where are they supposed to be placed ? Is this correct ? I didn't stick the adhesive backing onto the spots you see in this photo just yet, but I'm pretty sure this is where they should be placed ?!:
Here you can see the NEW C-type power supply along with the adapters I'll need for the monitors I'm going to be using:
I haven't tried to insert my microSD card image from my RPI3B+, I'd be surprised if it works and is compatible with the RPI4, very likely I'll need to start from scratch and just rebuild. I did notice that on retropi's website : "The latest pre-made image of RetroPie is v4.4 – released April 14, 2018." I'm not sure if anyone tested that yet on the RPI4 yet but that's my next step...
And after reading this thread a bit :
https://github.com/RetroPie/RetroPie-Setup/issues/2749I'm going to likely need to wait for RetroPie v4.5