You have an early thumb push opener model that was built when E was the lowest grade Lefever. The insert in the tip of the forend would have been made of a dark colored buffalo horn. It will take some care to remove the piece of wood that was used to replace the missing horn tip without doing damage, especially if glue was used in addition to the brads.
It looks like your gun still has a lot of original case hardening color on the sideplates. I notice that the forend iron is not attached to the wood, and the forend release and escutcheon is also removed. I hope it isn't missing because finding a replacement would be very difficult. The buttstock appears to have very nice figure and looks to be in pretty nice shape. If you decide to have someone refinish it, make certain it is someone who knows what they are doing. That wood is over 125 years old, and Lefevers tend to crack or split at the head of the stock above and below the sideplates where the thin and fragile wood meets the action. Great care must be taken during any disassembly. It is also for this reason that only low pressure low recoil loads should be used if the barrels are un-pitted and still safe to fire. You may be able to find pictures of the forend checkering when one comes up for sale on Gunbroker or other online source. Or enough of the original pattern may still be seen after stripping the finish for a good stock checkerer to re-cut it exactly as it was originally. Here's a pic of the forend checkering and the horn tip.
A good restoration will not be cheap, but a cheap restoration will likely do more harm than good. You would be better off leaving it as is than letting someone screw it up with incorrect techniques and materials.
