I found a exploit! On the first level (not the tutorial, the glass roof one), restart a few times, and you will get all the weapons, however, it may not work and you might try a few times. All credit goes to Belfos.
Note: I read some game files, and it turns out different buddies are good with different weapons. for your friend Hank Hanky, his level for automatics are decent, but his aptitude for long barrels (shotgun) and blunts are very effective. Kelly though, is good with both blunts and blades, and very good with pistols and average with automatics. Hope this helps!
for those who are dissatisfied with their car's paint job and hate fueling their car, just go to the car shop and switch to another car you have and switch back. bam, the car will have a new paint job with full gas.