Most likely, they have never been changed, so being that they are original just make a chalk marking along the floor pan for placement when you reinstall the new hoses. When you get to the heater core, using a sharp knife, cut the hose off about 1" away from the hose clamp. Then remove the hose clamp, and using a very sharp knife or a razor, make a longitudinal cut along the hole that is on the heater core nipple and gently pry the hose off of the nipple by inserting a flat blade screwdriver between the cut lines and rolling the hose off the nipple. When it comes time to install the new hoses, use KY jelly on the nipple and the inside of the hose to slip it on without breaking the heater core nipple. Make sure to put your hose clamp on the hose before installing it. Tighten until you can see the rubber bulging through the small groves of the worm drive hose clamp. Be careful not to crush the heater nipples. If you need additional hose supports you can make them out of flat steel stock and roll the edges over a piece of 1/2" steel pipe.