I've acquired at some stage this 1976 US $2 bill which seems to have gone through the post. It is franked '30 June 1978 Baltimore MD - First Day of Issue'. I know some people franked these bills on the actual first day of issue, but that was April 13, 1976.
A 15c US stamp was issued on 6-30-78 showing Fort McHenry, and I'm wondering if one of these was previously attached to the bill, but has since fallen off.
The bill is not printed off-centre as shown - I cropped the image a bit too much after scanning it!
Is this bill worth keeping or should I spend it on my next trip to the USA?