Transactions made with current clients have outputs like
OP_DUP OP_HASH160 <pubkey hash> OP_EQUALVERIFY OP_CHECKSIG
where transactions made in the early blocks of the block chain have outputs like
<uncompressed-public-key> OP_CHECKSIG
And under the hood, these are treated the same way. This is simply pushed onto the script interpreter stack when it's spent and then the spend script operates on the stack.
And the same spend script - namely
<signature> <pubkey>
works to spend either kind of output.
Is there any problem with a transaction containing an old-style txOut if it were made today? Would it be considered non-standard and not relayed?
