73 carbine front sight height?

I've got an M73 rifle that is by all accounts a Bannerman's parts rifle. The breech block, receiver and barrel are 1875 vintage with no proofs on the barrel. The lock is an 1884, but the hammer looks like it's 1860s vintage. The long wrist stock has a paper liner in the barrel channel and has been cut rather roughly to carbine length, as has the barrel.

When the barrel was cut, whoever did the work installed a useless front sight that is offset considerably to the right. I would like to replace it, but I don't know how tall the front sight should be.

Could someone give me that dimension?

Thanks, Greg