No you do not have to split it to replace the line. The service manual points out how easy it is to fish a new line up through it. I'm sure I posted that info and page from the manual before.
Very very nice thirty-0-six you got there. Gregg is correct that they were just a early 306 model. Around 72 if I'm not mistaken and yes that bar is what could have came on it originally.
Thanks! It is another one of my FREE saws (Did I mention how much I like gettin' free stuff?) I got it, and a 3400, from a guy in a package deal with a couple hedge trimmers, a back pack blower, hand held blower, a couple weed eaters, and a couple Mac chain saws. Sold all of the other stuff, except the Mac saws, and got my money back, and then some.