[R-390] Serial number matching

[Tim Shoppa]

> Looking at your deck serial numbers should not be taken as any thing
> other than curiosity.  Some guy will sell a matched receiver [...]

Certainly, a curiosity.  And it's not that either of my radios had
matching modules - I was more struck by the fact that my two radios
(each of which is a Heinz 51 mix!) had serial numbers that differed
by only 1.  Sort-of-like twins separated at birth but reunited after
4 decades.

Of course, the way R-390Aitis has taken over here, I won't be
satisfied until every single R-390A has met its brethern here in
my basement :-).

Tim.