The answer is YES, maybe.
I like to incorporate these “training races” into my preparation for my target races because it’s more fun to have support, other people to run with and cheer me on, and possibly a medal and food at the end, than to just do a long run on my own.
But it’s important to be disciplined. For long runs, as we discussed in Smart Marathon Training, it’s important to go at a pace that’s slower than your target race pace by a minute or more. This will help ensure that you don’t put too much stress on your body.
In a race setting, though, it’s tempting to get caught up in the excitement and start to race faster than you were planning to. If you don’t think you can be disciplined enough to stick to your plan in your training race, it would be best not to do it. But if you can do it, then plan to stick with the mileage you had planned for, and either add some more miles before the race, or perhaps later in the day (but it needs to be the same day) or to drop out when you have hit your target distance.