I have just got a 8900 from orange (uk) and i have just installed the desktop management software on my pc.
It tells me there are a number of updates for my phone. I am very much a believer that "if it's not broken dont fix it", as i hear some people find their phones lag and run slowly if they update.
Currently-
8900 running V4.6.1.101 with a platform 4.2.0.72.
I get a similar message everyt ime I hook my BB up to the DM. I just click "ok" and it searches and does whatever it does and comes back and says there are no updates for my device.
I have a hunch that the same thing will happen to you. Its quite annoying, however it happens to me EVERY time and it has NEVER found new software to update. Sounds like you may have the same glitch, I would just say yes and let it do its thing; I'm really thinking that it will not find anything in the end anyway.