If it is genuine, then that's a very nice coin indeed, and I would wear gloves when handling it.
Unfortunately, I don't think it is. I can't seem to find a great deal, but from what I've read, the 1927 Irish Free State Shilling has medal alignment and is 4.67g. See
here (Page 4 labelled IR005)
(Edit) Not much info here either
http://www.ngccoin.com/price-guide/world/ireland-republic-shilling-km-pr6-1927-cuid-32032-duid-93937 http://www.facebook.com/NumismaticsUK
I'm not an expert in any kind of coins, but I reckon I'm good at research and will do my best to help. Feel free to tell me my identifications/valuations/gradings are wrong. It's the only way I'll learn.
