I remember the HotVWs article on the Rajay (correct spelling); I think it was from 1970. My dad had a subscription via his office. The Rajay engineer was shown to be an "older guy" (maybe late 50's, old to me as a young teenager) with glasses and wearing a suit. I'm certain that the Beetle was a '70 with a single-port engine. I also vaguely remember that the HVWs article only had B&W photos but the Beetle had a light color- such as ivory, beige, or pale yellow. I just went thru my old issues from '69 thru '71 but did not find the specific Rajay article, though unfortunately I don't have all issues from that time period.
In 2021 at a large VW meet in Connecticut I spoke with a young man displaying his father's beige '74 Standard Beetle. He said his dad was a mechanic at a VW dealer and installed a Rajay kit onto the brand-new Beetle after hours before it even left the dealer; thus a 1600 dual-port engine. It was a "time capsule" engine modification which survived all these decades. I asked him if he knew the correct spelling of the company, if it was Rah-Jay (per the spelling and it's plausible) or Ray-Jay (because it rhymes and is thereby more popular)- he did not know.
Differences in your photo to mine is that the original was using a stock Solex downdraft carb; the one on the '74 was likely an updated design with a side-draft Bendix carb which obviously shortened the intake mixture path compared to the Solex. Also the fabric exhaust wrap instead of bare pipes. I remember early Rajay photos having aluminum-foil type insulation on the pipes.
Here are a few of my shots from theSamba on the engine-