"W" Are They Circulation Or Proof Like?

^^^^ Correct, they were only issued in uncirculated set / mint sents...brilliant uncirculated sets.....what ever you want to call them. I notice that lots of sites and people refer to business strike coins as PL or BU which is incorrect. A business strike can be MS, while a PL is for coins from sets from 1953 to 1967 and NBU is for coins from sets from 1968 to present. So any 1998w coin is from a set and is NBU. IMO

I have the 5 cent, 10 cent, 25 cent and 50 cent "W" mint marked coins in my Canadian coin binder. They are same finish as the RCM Mylar packaged BU sets from the 1970's and 1980's. I highly suspect they were made from chrome plated dies. Beautiful coins, they are.

My 2010 Charlton says MS, with a NC designation below it. Specimen set coins are SP and proofs are PF.
I personally would label them BU as a 1978 set I have calls them uncirculated.
I think the real answer lies in what they do to the dies that strike them. If they chrome plate the dies, then they are PL. If they do not, then they are BU.

I would label them BU, for PL is only from sets from 1952 to 1967