Could be, Brian.
Both of these (c3 & c5) are in garlands collected by John Bell of Newcastle. He bought them from Lilley in 1848. On the back of G5 it says in JB's hand 'The old garlands in these volumes are printed by J White who died in 1769, and T Saint who died in 1788.

The cover of G4 (The Bottle and Friend's Garland) has a cut on the cover of 2 lovers in a pleasure garden and Cupid with b&a in top rt corner. G5 was probably printed by Saint and is very similar to G4. That would make it more like 1780 than 1765. Neither has an imprint. Unfortunately. Unfortunately even though I have catalogued this garland twice I can only afford to copy out items by hand and type them up later. I can't afford their photocopying charges.

It might well be that both garlands were printed by the same printer. The 2 texts are almost verbatim the same and the first song in Damon & Phillis's Garland is in fact 'Bottle and Friend'. Again it is without imprint and my own impression I recorded was c1800.

To be on the safe side I would feel happier dating them c1780 to 1800.