The rules haven't change, but very few officers would bother with that as far as should you be registered commercially if the commerce your involved in pertains to a Bigfish Tackle.
For the record......we were instructed at in-service training if someone is driving down the road advertising on any vehicle then they have to be registered commercially regardless of size. The vehicle doesn't have to be large enough to require a CDL license. I stopped a motorcycle a few years ago that was placarded (HAZMAT) he had a small amount of nulclear waste that he was transporting to his company to be disposed of. Will anyone catch this, there is no commercial MC plates. Regardless of what everyone or anyone thinks the advertising is "in the furtherance of commerce", the advertising is "commerce". I wouldn't be surprised at some point in time if an insurance company new someone was involved in a business and wouldn't pay a claim if there was a crash.
Don't check with your insurance company they don't know squat when it comes to the law. I stop vehicles that are registered for 5000 lbs. but you need a Class B license for the vehicle, which means it has at least g.v.w.r. of 26,001 lbs or more. The truck I am thinking of had a G.V.W.R. of 50,000 lbs. and was only registered for 5000 lbs. Anyone can walk into an insurance agency and the agent or its employee will do what you ask. They want your money. We were also told to go after the guy who drives down the road with a couple of yards of sand, ten bags of concrete and tools in a truck with dried concrete covering truck if it has a PC plate on the truck,because it is painfully obvious he is a mason. I don't know of anyone who has done that though. Calling the RMV isn't such a bad idea but the chance of you getting the right answer there is slim and none also. And just because they say it one thing and you find out it another is no defense to any citation you get based on something an RMV employee gives you. You have to remember an RMV employee who answers the phone is probably a secretary or clerk, not a lawyer. Just because they answered the phone doesn't mean they have any training whatsoever in law. There is only one lawyer that works at the registry and you'll never get close to him. You may get to speak to his aid like I do once in a blue moon, but you'll get no closer than him.
Larry is anyone going to stop you I doubt it. If you were going to get stopped it would have been with an oil tank in back going to the disposal business not because you are transporting all that wood. Besides I don't think you'd find a judge that would fine you for advertising on the side of your truck if you did get a ticket. Just use everyones favorite defense, "I didn't no".
One more thing. To register a motor vehicle to a business you have to be incorporated in Massachusetts........Anyone can register a truck commercially to your given name. Its cost $125 to $135 buck for your size vehicle.I would think. And you'd be covered.