I was about to point you at that site this morning! non-sport.com is an excellent site run by Todd Riley. I help maintain the site and added or updated most of the information about the "Bazooka Joe" card series. That first set is listed as 1972, not 1970, but many guides list it as such, but I provide dating info that squrely puts it in 1972. The un-numbered set and the 1975 set share the same puzzle backs, so your recollection seems to provide more evidence the un-numbered set was issued sometime between late 1972 and 1973. Dating some of these less collected Topps' issues can be difficult and "hobby knowledge" can be hard to correct when evidence proves otherwise. There is ample evidence that "Civil War" was issued in the summer of 1961 for the centennial celebration... updates to the ACC, stamped shipping cartons, etc., but the hobby still continues to date it to 1962, including the TPG companies. If we could find unopened packs of the "Bazooka Joe" cards from 1972 through around 1977, they might be the only way to conclusively prove dating.
Funny that you should mention
Civil War News. I would've thought that Topps would release
Civil War News Heritage in honor of the 150th anniversary of the American Civil War (2011-2015), just as they released both
Mars Attacks Heritage in 2012 for the 50th anniversary of
that series (which, as all of us here know, was originally released in 1962) and
Mars Attacks: The Revenge! in 2017 for its 55th anniversary, but they didn't.
Two more missed opportunities were in both 2008 and 2018 when Topps, if they had even
thought of doing so, could've released
Dinosaurs Attack! Heritage for either the 20th or 30th anniversary of
that series (which, again as all of us here know, was originally released in 1988). Again, both times they didn't.