Shimano powermeter crank fit?

[SirDoh]

I came across a used Stages2 powermeter crank sold as a 105 (5800)
Is there any reason why it wouldn't fit/work on Ultegra 5750 or Dura-ace shafts? I thought that the Hollowtech II splines were pretty much standard.
I know this question seems too simple but they offer so many different models. What is the difference? Is it just styling or is there a more complicated answer?

 

[CAMPYBOB]

Just styling. I have a 5800 105 rig and the older and less expensive 5700 model Stages had on closeout would have worked on my new BB spindle, but they didn't have 172.5 in stock.