Sonoff NS panel to M5-C relays

I have M5-2C installed with not an efficient way to a stone surface. It is very difficult to exchange tha main (back) body. Few minutes before I replace the front panel with a NS panel and seems to work.

can anyone confirm that there is no problem with this? Are the back parts the same on M5-2C and NS panel? Is there any problem with PSUs or something?

Thanks

Anyone?