Like the title asks, the 2005 pictures I’ve seen have a more squared clamp. 

Will the roof cross bars interchange? Specifically from a 2001 to 2005?

I can’t find specific part numbers for either model. 

i don't think so.   a local craigslist search usually gets the ones you need or check car-part.com

 

I ran 1" (at least i think it was) conduit with UBolts. Sounds rigged, but they are stronger than the regular clamps. 

-Justin

 

2001 and 2005 are different Generations so I don't think they will interchange.  Subaru parts website does not list part numbers for roof cross rails for either model year

91151AE000 R34 for 00-04 Outback

E361SAG020 for 2005-2007 Outback