I am not aware of a Remington sxs with a side lever. Of course that could be lack of knowledge. I would love to see pictures of this gun.
Remington made the Model 1893 #3 which was a single shot. It had a top lever, with a cocking lever on the side.
To my limited knowledge the earliest sxs they produced was the 1873, but it did not have a side lever.
The 1873 was designed by Whitmore. They produced this "lifter" as models 1873, 1875, 1876, 1878 and 1879.
Starting with the Remington Hepburn in 1883 they produced a series of rifles with a side lever.
This is the Model 3, single shot.
![](http://i27.photobucket.com/albums/c181/tintype1/shotgun_general/Remington_Single_Shotgun_3_1893.jpg)
1873 Whitmore Lifter. You lifted the top lever.
![](http://i27.photobucket.com/albums/c181/tintype1/shotgun_general/Remington_1873_Whitmore_lifter.jpg)
1883 Remington Hepburn
![](http://i27.photobucket.com/albums/c181/tintype1/shotgun_general/remington_1883_Hepburn.jpg)
Yes there were guns made in Belgium with the Remington name on them. This was under contract from Remington.
Pete