A gentleman under the name of JC5 often posts here - he is your best bet.

The models between 1897 and 1904 when they dropped the "Lee Speed patents" marking are very similar. I belive until 1896 they only produced the #1 sporter with the ribbed barrel and I
suspect that is when they introduced the "for cordite only" marking.

Not exactly much help - which model do you have - Pictures would help.