Help IDing Steyr 88/90 unit marking

[ShtLE303]

In the process of cleaning a Steyr 88/90 that came out of Ethiopia. Other than being filthy, the rifle is in fantastic shape. AOI (Africa Orientale Italiana) stamp on the butt, it's part of war reparations sent to the Italians after the Great War. There is a unit marking on the buttplate that I'm hoping someone could help with. From what I can see, it's '54R', then '21508' (or 9)

Barrel is also stamped with 'Wn 88', with what appears to be a Belgian crown over ELG, but I'm pretty certain Belgium did not supply the AH military with barrels. I may be wrong of course.

Looking forward to any thoughts...pics of the entire rifle soon.

Edited 25 September by ShtLE303

[AndyBsk]

It could be the barell was reproofed postwar, there existed some conversion done in Belgium. The unit is as mentioned a austrian Infantry Regiment nr.54 Alt-Starhemberg when good readed, it should be located in north area of Moravia in Olomouc. The rifle could be remains of equipment in italian front area of austrian units after oktober 1918. Even later reused by italians in colonnies. Question remains too, about all parts are matching? as the barell could be proofed in Belgium as part of later exports over belgian arms agent.

Edited 26 September by AndyBsk

[ShtLE303]

Definitely wasn't rebarreled post war. As stated, it's stamped Wn 88. After a little research, it appears that it's not Belgian.

This rifle was a part of a cache that came out of Ethiopia and sold through a company called Royal Tiger Imports. 

[AndyBsk]

Unfortunally the stamp is not fully visible and blurry, possible its not a belgian ELG proof, i couldnt say its or not. Not enough visible.

[Rafal1971]

[AndyBsk]

Thanks to Rafal details, it looks like ELG proof on barell, over this in rust area is too some stamp, similar parts pictures dont help by designation.Should be cleaned and presented other stamps of the rifle, for overall opinion.