Yes.
Any sax is worth overhauling if it's a good one regardless of how much or little you paid for it. What you paid for it shouldn't even be a factor determining how much you're willing to spend in maintenance.
If you drive a 20 year old car that you paid little for, you still have to get it serviced and fill it up when the tank's empty, plus tax and insurance and testing and none of that is ever taken into account or adjusted to reflect the money you spent on buying it. You never bargain with your garage at the cost of a service or with your insurance company that you only paid so much for it and any repairs or insurance should be to a value you think is right for what it cost to buy, so don't apply the 'is it worth it seeing I only paid X amount' or 'can you do everything on it for next to nothing as it only cost me X amount' as that won't get you anywhere.
True you will often spend far more on an overhaul than some instruments cost TO BUY, but that's neither here nor there - if it's an instrument you want to get full playing potential out of, then it's only right you spend whatever it costs to get it in full working order.
I've had some people complain that I charge too much for a service - one player moaned it was 10% of the cost of her Yanagisawa A992 (and she wasn't the one who was likely to be paying for it as 'daddy' would be). I charge the same price for a service and overhaul regardless of the make or model as it's still the same work being done and I definitely don't base my pricing on a percentage of the value of any instrument or on how much or little someone paid for their instrument as that's not relevant to me. What is relevant is getting their instrument back into fully playable condition and I'd charge the same amount to service a Jupiter 767 as I would to service a MkVI as it's the same amount of work.
I bought a Yamaha YAS-62 for £320 which was in excellent condition although it had been repadded with sticky pads. As it was a YAS-62 I could justify stripping it down and rebuilding it. Likewise with a YAS-32 I bought before for not much more than that which was a great instrument and also well worth overhauling which I did - when it came to selling the 32 on eBay I had several timewasters saying things like 'I'll give you £200 for it for a quick sale' which was just taking the pi$$. In both instances the cost of the overhaul would have been in excess of how much I paid for each instrument if I was to charge it out. You WON'T get your money back on some instruments, but you will still get a good instrument if you're willing to spend the money on having it overhauled. I got £500 for the 32 in the end which was £50 lower than I was selling it for so on intermediate instruments you very often won't get the money you put into them back just like you wouldn't when selling a car you bought for very little and spent a lot more on it in maintenance and running costs. Chances are these older ones may be better than a lot of the new ones and it's also far less costly to buy an older instrument and have it fully overhauled than it is to buy a brand new one.