Yes, balances over 50 BTC may not be fully reclaimed.
IF davout pays out anything at all.
Balances under 50 BTC may not be fully reclaimed either. All they've said is that wallets with more than 50 BTC will be handled differently, which makes sense. They haven't released any information on how exactly they will be handled.
INSTAWALLET SERVICE NOTICE
In the next few days we are going to open the claim process for Instawallet balance holders to claim the funds they had stored before the service interruption.
Important information on claims submission:
For the first 90 days we will accept claims for individual Instawallets. Your wallet's URL and key will be used to pre-populate a form to file the claim.
After 90 days, if no other claim has been received for the same url, your Instawallet balance under 50 BTC will be refunded. If several claims have been filed for the same url, we will process those claims on a case by case basis, under the presumption that the claim we received first belongs to the legitimate balance holder.
Claims for wallets that hold a balance greater than 50 BTC will be processed on a case by case and best efforts basis.
There is are a couple of valid suspicions to hold, one of which is that it's taking oddly long to implement what should be a fairly simple claims process of "give use the details associated with your wallet and if no one else wants it you get it". However, this could be just because davout really really wants to make sure there aren't any security flaws in this claims process, after he fucked up the service itself so royally. So that's not currently a huge suspicion of mine, but time will tell.
The most valid suspicion, I would say, is that davout intentionally did this and intends to do everything legitimately from here on out, but engineered this specifically to make money off the wallets that never get claimed.