[Hammarlund] HQ-170 series question

[KS4S Nyles]

Is there any significance to the HQ-170's that have the darker paint on the
front panel and cabinet vs the lighter paint series?

The darker unit that I have also has the "black mask" I call it around the
two dials. (That one is actually a 170-A).

The lighter gray ones that I have are plain 170's.  Just wondered if there
was any notable difference other than the usual "A" series to "non-A"
series.

Thanks,

Nyles  KS4S
Lumberton, NC