Ok, well here's something dead quick and the strings have now been worn out - but I still think it has that nasal snap on the top end that I would usually characterise with Marcus and 70's jazz bass. Obviously bottom end is lacking because its a Squier VMJ with naff PUs. Would be interested to hear any slap examples you think are obviously 70's spacing that differ a lot from this.
https://soundcloud.com/user-220370308/squier-vmj-quick-slap-riff/s-pxqpeCyd4Lx