Vintage Wrangler jeans trying to date/get info

Early 70's.  They introduced broken twill in '64.  They then switched to the black/gold label sewn onto the felled yoke seam, after they dropped the Blue Bell mark from the natural colored labels in 1966.  Keep in mind, the factories didn't abide by these dates, just corporate, a common theme with any brand, so you will see wartime buttons get used until they ran out, then you'll see, more specifically, neolite back pocket labels or fly labels get used until they ran out, so even though the Blue Bell was dropped in '66, you could still likely find items for several years run out of the IN or NC or KY factories that were using them up.  Key thing to note here is that in '66 the 13MWZ was introduced, and then 1970's is when boot cut or flared leg pipes were added into the product mix.  This puts you jeans after 1970, but prior to the fly label transitioning to a vertical tape zig-zag sewn into the fly with information reading parallel with the legs, rather than your example, which reads parallel to the waistband.  This is the second iteration of the fly label reading only Wrangler, the first would have read "SANFORIZED" beside "Made in USA", then this version, prior to the last natural tape label that drops the Made In USA from the tag altogether.  The brand opened a factory in Europe in '62, and as it grew, it was likely that by dropping detail lines like this that it enabled upticks in volume of ordering, so they observed economies of scale.