Thrift store cast iron that doesn't quite add up

[MaybeMeh50]

How's it going? Long time lurker finally stepping out from behind the curtain. I came across a few cast iron pans at a thrift shop that looked familiar but didn't carry any brand. I recognized no Lodge stamp, nothing. They had a slick finish but no oily feel and the seasoning guide said to bake them upside down with oil, which raised a few eyebrows. Figured I'd stop lurking and start asking questions before I fire one up and make a mess.