-500's are a lot shorter than the -600's. 735's have only one over wing hatch and the 736's have two, easiest way to tell the difference,the 735 is a "classic" 737 and the 736 is a 737NG as another way to tell.
There is a huge difference in building them and fixing them. And for your FYI, I spent a lot of money training for aviation maintenance, I have a college degree, I am certified by the US Federal Government to work on aircraft, yet that same government classifies A&P mechanics as UNSKILLED Labor.
We are more a totalitarian state then you think we are, I don't know what fantasy land YOU live in, but here in the US, there is NO democracy, you are made to only think it is. I did not choose a single person in any office, any where. The majority of people in this country ARE cattle and SHOULD be treated as such, and now we would not elect someone else because we just keep putting the same people in. Demonstrating how to commit a terrorist act crosses the line of free speech and this guy SHOULD HAVE BEEN HUNG for putting out such garbage.