The identification strings of the Nokia 3250 seem to be broken, at least in firmware version 3.09.
The User-Agent of the WAP browser in the phone is:
Nokia 3250/2.0 (3.09) SymbianOS/9.1 Series60/3.0 Profile/MIDP-2.0 Configuration/CLDC-1.1
Note that there is a space before the model number, all known previous Nokia models have had it concatenated: "Nokia3250/2.0 ...". This may break some device detection logic on web servers when deploying MIDlets.
The value of the "microedition.platform" MIDP system property also seems to be broken, a value that I have seen logged is "Nokia/ 3.09".
Note that I have not had access to an actual Nokia 3250 device, I only have observed the logs of a web server supporting a MIDP applicaiton that uses http networking. Don't know, but firmware version 3.09 might of course be a pre-release version (in a prototype device) and all this might be fixed in firmware versions for public release.