I replaced the 41 year-old Pirelli seals on my Alaskan when I bought it. Totally frayed and not sealing at all. Reduced to fringe in most places and worn away in others and not sealing out air, bugs or the weather.
As to your options from Home Depot or a garage door company....
As well designed and shipshape as Mr. Hall could make them back in the day....ya hafta ask yourself one question. Why didn't he use those options as they are clearly CHEAPER alternatives? I'm sure he spent an amount of time considering all options and ended up with the Pirelli seals he used and which are used to this day If I understand how the Alaskans are currently in production. My guess is he found the Pirelli seal option to be the BEST, not the CHEAPEST. Take your cue from there....
In any event...the heat and the constant abraision caused by raising/lowering the upper half need a sturdy product that will not wear away, get hard and chip/flake off (well, mine did but only after 41 years!) and conform to the irregularities they slide up/down over.
"Any job worth doing, is worth doing RIGHT!"
It is just a one or two day task. Probably simpler and easier than the alternatives suggested and, if correctly done, you can probably look forward to good sealing in both the raised and lowered positions with regard to air leaks, dust intrusion when driving and critter defense to an extent.
It's your Alaskan, so it's up to you though...