As a simple rule of thumb, Lebels have a tubular mag under the barrel......Mannlicher Berthiers use either a 3 or 5 rd en-bloc clip.
The 2 most common Lebels are the 1886/93 (full length), and the 86/93 R-35 (18"bbl carbine). Either in full military guise are worth 250 + depending on condition. Original 1886 models unmodified to 86/93 specs are rare.
The common Mannlicher Berthiers are 07/15's (full length 3rd mag), 1916 Carbines (5rd). The earlier 3-rd 1892's are a little harder to find. There are versions (certain 1890 carbine variants, and the 07/15/34 Long rifle) that are quite rare. Unmodified 3rd long rifles are getting a little harder to find as well....
If you're gonna shoot them, see if they are proofed for "Balle N".......an "N" stamped on the top of the receiver. If they are cut/sporterized, I'd pass.......like the poster above said.....they would turn into money pits.....would never be "original"......and 8mm Lebel isn't the cheapest round to shoot either.
For those who think an M44 Mosin, or 95 Steyr kicks and produces a big fireball, I say touch off a round of 1948 Hotchkiss MG "Balle N" in an 1892 Berthier carbine........holy sh*t !!!!!!!!