Looks very much to me like an 1804 and also the "spiked chin" variety, very nice, congrats!!!!……..and I would not touch it at all, you would lose detail and I think it looks fantastic as it is! Congrats!
Warm up some hydrogen peroxide in a microwave and dab it with a few q-tips to clean off any residual dirt. There's a great product called Verdi-Care which you can use to hydrate these coins and make them present better. Drop me am PM--if you're out my way I can give you some.