While I'm sure the pump can be changed at the roadside, having done the job, I would really prefer to do it in the comfort of the shop. It's not a difficult job, just a bit fiddly. As I recall, even taking the time to clean everything up in the rear wheel area (before the install to prevent dirt ingress), it was only about 90 minutes start to finish.
A genuine Walbro pump should last for a very long time, as in many years, as they are used in OEM applications that routinely see 150k+ miles of life. As for is it worth it to change preemptively, hard to say. If the dealer used a decent brand pump then you should be good to go for years. If they used the same no-name POS that came (with my car at least) from the factory, then I would replace it now, as it probably failed while I was typing this.
