Re: 1964 Fender Mustang resources
Not the correct decal at all; pickguard looks a bit "new" as well, white pickup covers were usually found with tortoiseshell pick guards/white finishes, one or both of those things have been replaced as well as the paint. That's a great find though; 24" "full" scale, if it's a true '64 then that's a bit rare, I have seen a lot more 22.5" scale Mustangs from that year.
As stated, tuners should be white oval button Klusons; are those trapezoid F-tuners? they could be from a later Mustang, or something else entirely, as the slots look funny to me. The neck will be stamped, no pencilled date.
Mustang wiring guide:
http://www.shortscale.org/wiki/index.php?title=Wiring_A_Fender_Mustang
I love Mustangs, but a lot of the stock pickups are anemic; by their nature they're not very resonant guitars and the design of the pickup mounting and covers along with the relatively high bridge often means they can never be raised to a proper level, so they benefit from hotter pickups; don't remove original pickups though

The guys at Offsetguitars.com know a lot about these.
Aside from the funny decal, the headstock is the earlier, smaller '64/early '65 shape as mentioned; see my '66 , much more bulbous :
(Half the decal on my '66 is reproduction (the "Mustang" portion, "Fender" is original,) and some person added a string tree at some point

But this is more like a standard decal shape at least, although an actual '64 decal is different, and different still from the 70s/early 80s decal.)