I recommend that you take the unit to a Hobart service center, and have it checked out and serviced first. Then, study Hobart's prices for a new bowl, dough hook, flat beater, and wire wisk. You'll have use of your mixer then, and you'll also have a new bowl and attachments to use. You can keep the old attachments to preserve its value, if you feel the need to. Hobart has been making this model for years, and has been servicing it for years, and little has changed in its design from the looks of it. You can, in fact, probably still get parts for it.
I have seen old Hobart N-50s sell for around $250.00 on EBay, in unrestored condition. Others end up restored to a like-new condition, with original factory-spec decals, and then go for around $800.00. If you can have it restored to an original finish, complete with original decals, then I would say it may be worth more because it would be preserved and in service. A KitchenAid Model G is also usually worth more restored if it's done correctly and to the manufacturers specifications.
Here is some more information to look at: If you go to
www.mixerfixer.com, you will see that the prices are considerably higher for a unit that was restored, then it was before it was worked on. A Hamilton Beach Model B is selling for $525.00 there, yet was most likely acquired for less then $75.00. A KitchenAid Model 3B is going for $275.00, yet they have been found in as-used condition for less then $50.00. The fact is, none of these machines where new when the restorer acquired them. They were sold as antiques. Another site to consider is
www.decodan.com. DecoDan has had some of his restored mixers featured on major publications, so he may have a long waiting list. There are many antique mixers out there. And there are far more Hobart N-50s then there are KitchenAid Model Gs. Both the KitchenAid Model Gs and Hobart N-50s are still in service, and they are likely to outlast most of us.
MrCoffee