The brass thing is a simple drain tap..... so you can properly drain the block ...
As for the thing on the core plug I have no idea...... I bought this bottom end from a guy that has it built from a brand new block.... fully balanced. .. pistons weight matched. Ross - end to end and overall etc... and balanced crank.... he had it in his cobra kit for 14k then went to a 4.6..... the other core plugs have temperature stickers and them and it's never been above about 95..... hopefully with the cam I chose and all the bits I'm using I'll have a super smooth motor.....