Model 1899 carbine, number 229043, was likely built, around September or October, 1899, at the beginning of model 1899 production.

It probably had a model 1896 carbine sight installed, when first completed, with an 1896 'rifle-type' hand-guard.

The 1898 carbine rear-sight was short lived and they are rare. I believe Grandpa's Gunparts is displaying a model 1898 Rifle sight with the corners altered. This rifle sight appears put together from parts and is not correct for a model 1899 carbine. There are cheaper temporary options - 1901 and 1902 rifle sights, (not correct but useful and relatively inexpensive).

The model 1899 carbine hand-guards with sight protecting lobes came later, when it became apparent sights were being damaged in saddle-scabbards. (Around 1902, IIRC).
Earlier, rifles and 1899 carbines were sharing the same hand-guards.

I don't know if you are selling the carbine on GB or bought it?
(FWIW - The front-sight blade in the original base is a commercial blade).
If you are selling it, I would recommend selling it like it is.
If you bought it, it will cost about $500 to patiently get correct parts. (It will still be a 'parts gun', worth about $900).