The 401 feet will fit the 301... even the zigzag ones although the 301 doesn't. The other bits, motors, plates and etc would be something I'd consider at the right price. If I didn't need it, I'd use it as trading stock, but I have many machines. Giving away a throat plate to someone that's been looking for that very specific one - can begin a great vintage sewing machine friendship - and those are very nice to have. If you have the space, and the interest, offer the person what you think might be a reasonable price for the lot - since they don't seem to know what they have. Sometimes, at estates sales, it's not about the profit line, it's about never having to fool with that stuff ever again - they may just want it gone. You help them make it go away, and they may help you with a price.