I think the Suwa dials were standard on the Japanese domestic market watches (the ref 6306) which was only in existence for maybe 4 years based on what I've read (76-80). [This could be incorrect, if someone knows please correct me]. By contrast the 6309 (overseas reference) was produced for longer period (76- 87 I believe).
I also have read that the finishing on the case and caseback of the 6306 (domestic model) was superior to the overseas reference 6309. And, the 6306 domestic reference had a different movement which hacks, I don't believe the 6309 hacks.
Looks like yours is the same dial alright (although the picture is not clear enough to make out the exact text).
Fun watches, lots of personality.