--restore-deterministic-wallet the same Monero address is restored but the md5sum for my
wallet.keysis different. Are Monero wallets truly deterministic? Is the change in md5sum cause for concern?
The encryption used by the keys file is randomized. It uses a key derived from your password, and an IV (initialization vector) which is randomly selected. This is designed to prevent an adversary from determining which parts of the file are the same, and which are different, if you encrypt two files (or two versions of the same file) with the same password. So even if the contents of the file were 100% the same, you would still get a completely different (well, ideally, 50% different) file.
wallet.keys file has the date embedded so the md5sum will change every time you restore with
Yes your wallet is deterministic. The new md5sum is no cause for concern because as explained by fluffyponyza:
If you got the same address then it restored both your view and spend keys perfectly. Remember that this is not Bitcoin. With Monero, your address is not a hash, but it's literally your public spend and view keys. So checking the address is all you need:)