126 & 124 3rd brake lights interchangable?

[Rooster300SD]

I pulled a nice rear deck from a Gen II W126 to replace the
very faded one on my SD. The Gen II also has the raised speaker
covers which will accomodate some larger speakers I have.
I figured the third brake light will be an added plus.

The plastic in that third brake light is very brittle.
Little tabs & parts breaking when I took it apart.
Are 124 3rd brake lights the same at the 126 ones?

Thanks,
Jeff