Error in Ethernaut's MagicNumFactory.validateInstance()?

I am doing the Ethernaut's MagicNum level and I have a doubt. One of the requisites of the level is the Solver contract to have at most 10 opcodes. Here is the way this is verified:

// Require the solver to have at most 10 opcodes.
uint256 size;
assembly {
    size := extcodesize(solver)
if (size > 10) return false;

return true;

But here size is the amount of bytes of the code: instructions (opcodes) + inputs. For example: mnemonic PUSH1 0x2a PUSH1 0x23 MSTORE, which bytecode is 602a602352, has 3 opcodes and a code size of 5 bytes. This means that what the MagicNumFactory.validateInstance() function is checking is the size of the code and not the quantity of opcodes.

Am I getting things right? Is the check well performed?