If the lugs not been machined off then it will be a bare replacement block which explains no YBD number as they came blank.

Is there a web coming off the top most bolt hole for the alternator bracket mounting, if so then its the YBF race version of the 500 block as we found out recently (I have a new one of these).

The 500 head is just a late 2wd head in essence, valves are exactly the same as any cosworth, and if its from a road 500 then the number should be YNO 415 on the front and you will see some machining work in the cast face of the inlets and a pair of dowel holes, if its a replacement then the head number will be YNO 627.