I'm not trying to de-rail this thread and I don't mind if my post is moved elsewhere, but I got the latest rule set from ETF2L. With the intention of adding clarity and clearing up any questions. (Just copied straight from the site)

THE RULE UPDATES!
There has been a tremendous amount of debate regarding the unlocks. To put the whole thing behind us, and hopefully allow us to focus on more important things, we will be adopting a “vanilla” ruleset.

Allowed unlocks: Blutsauger, Kritzkrieg, Übersaw and Crusader’s Crossbow.

Reskins of stock weapons (Lugermorph, Holy Mackerel, Frying Pan, Iron Curtain, Golden Wrench, Big Kill, Enthusiast’s Timepiece) are also allowed.

All other non-stock weapons are banned, including the Original.