Yeah, it looks like Uyigao are using the same design for many of their meters:
UA6243L - Digital LCR meter
UA33 multimeter series (B, C, D) (interestingly, there's no A version on the Internet)
Cheaper to use an existing mould set ( no cost for tooling, and they only have to pay for a new screen for the printing) and the case already had all the cutouts aside from the one they had to make a jig to drill out the zero adjust knob.
Looks like the hole is already on the rest of the meters as a power button... or a torch?
I bought a Uyigao temp gun recently (a few pages ago), the plastics are pretty nice, feels solid. Great device for USD 15 delivered.