This was the first arcade game I played at the Carolina Arcade Museum in Forest City, NC. I assume (with a lot of educated guessing to back it up) that this the original arcade machine and not a later version. The game has been super popular so there had been many re-releases over the decades. But I would say this is probably the original because it certainly feels more like a prototype. The unit is pretty short and the controls aren't super-comfortable.
Space Invaders was super popular for many reasons, but I'd say the main reason alone, it was more or less the most advance game of its time. In 1978, it took both Japan and America by storm. A popular urban legend (mostly myth with a little truth) is that Japan ran out of yen coins because of the game and had to ramp up production to meet demand.
I've played it many times over the years but never in the arcade. It hasn't aged well. It's slow, rather pointless, and super difficult. If it had come out in 1988, nobody would even remember the game. There's a reason most bowling alleys have Ms. Pac-Man but never Space Invaders.