Nope.
Check out TechManual. Weapons like the ERPPC and CLPL can't fit and so on.
Also forgot to mention, I don't know if the newer weapons (ERPULSE, CRACs, iHeavies etc etc) have been errated in yet so they might be viable until or if they are.
From what I see in the 2nd ED pdf (and no matching corrections in the 3rd ED errata), the following equipment/weapons are legal for Protos:
Angel ECM
Watchdog CEWS
Proto ACs 2/4/8
Proto Partial Wing
ER Flamer
Heavy Flamer
Veh Grenade Launcher
Chem Laser S/M (no Large Chem Laser)
Imp Heavy Laser S/M/L (yes, the large is included)
ER Pulse Laser S/M/L (yes, the large is included)
Streak LRMs
Proto Melee Weapon
Recon Camera
Veh Drop Chute Std/Camo/Stealth/Reusable