Yes, Facebook knows what you bought in-store and targets you accordingly

If you think it's just a coincidence that the Facebook ads in your feed are relevant to in-store purchases you've made recently, think again. Retailers that advertise with Facebook — Macy's and Dick's Sporting Goods are cited in the article — have the option of providing Facebook with hashed user data, including email addresses, names and phone numbers. Facebook can then match that information up with its users to serve up relevant ads.