Short answer: Yes.
Little bit longer answer:
While the value of what the IO itself modifies will change (per normal sidekicking rules), the set bonuses generated by your Lvl 25 set IOs will only be given through 22 (3 below) because of the Rules regarding IO sets.
Which make it interesting how you may want to slot for a particular build...
Thank you for the time...
@Travlr (Main) / @Tymers Realm (Test) 
And a bit longer yet.
Pretty much any multi-aspect IO if a level 25 IO (or lower) will not be effected by exemplar scaling. Any individual enhancement bonus with a value or 20% or less is not effected. As it happens level 25 dual aspect enhancements are equal or less than 20% in value. That is a LotG Def/End has the values of 12% def/20% endred both of which are equal or less than 20%. If the value was greater than 20% that portion would be effected by exemplar scaling.
For even more nitty gritty details:
http://paragonwiki.com/wiki/Exemplar...n_Enhancements
I'd realized I could answer my own question, and just exemped myself in Ouro to 45 and seeing if the set bonuses stuck. They didn't, so Tymers is correct. Thank you by the way.
Re Doomguide: Yeah, I knew about the enhancement scaling, my questions was about the set bonuses, and the +5 levels of powers, effectively meant that exemping made it so you didn't loose the IO set bonuses if you were exemped less than 8 levels, rather than 3. But thanks for that info in case someone wasn't aware of that aspect of exemping.
I'm working on a build for level 50 to use when exemping down, mainly for lower level TFs. Now I know that if you exemp more than 3 levels below the set IOs levels, you loose the set bonuses. What I'm unsure of is... lets say I'm going to run a Synapse. I get exemped to level 20, but I have access to my powers up to level 25. So if I have level 25 Set IOs, will those set bonuses be lost since I'm exemped to level 20?