Tommy beat me to the punch, Matt. If you really want to learn the difference between a real links course and all those posers out there, read Price's book.
The 160 number isn't far off the truth. I "know" this as I had to learn this (and far too many other trivial facts about links courses) a few years back for a TV quiz show. 50 of thse being in Ireland is also about right.
Mark R. is right too that there are a few courses in the low countries on the Continent which are fairly linkish. The ones I've seen, however (Royal Zoute, Den Haan), are more hybrid than pure links.
In the USA, the closest I've seen to true links courses are Pacific Dunes and Prairie Dunes. The defining characteristic is the turf, and not any proximity to the sea. Links turf is very scarce. For whatever reason, Pacific Dunes seems to have it while Bandon dunes does not. One course I know fairly well (Golspie) has 6 links holes, 6 heathland and 6 parkland, all within the same 120 acres or so. None of the Monterrey Peninsular tracks, including both MPCC courses, Pebble, Spyglass (1-5) and Cypress Point are links courses. Neither are Shinnecock Hills, NGLA or Friar's Head. It's all in the dirt (and the geology) and the USA just ain't got it!
Happy writing.