MI 6 Voices Cards Ambika Kit

I build a MI Ambika kit and I have two questions about the assembly of the motherboard:
1 - Is it possible to fix the 7808 and 7908 with a screw or it asks you a problem of mass or other?
2 - Is it normal C12 (2200uF) is not included in the kit?
Thank you for your help.

1. Yes, you can do that - I don’t think the heatsink is conductive.

2. Yes, it is not needed. It might be needed later in case some guy designs a third party extension (or new voicecard) which eats a lot of current on the +5V rail. This reduces the ripple on the voltage that enters the regulator, and allows more current to be drawn from the positive rails.

The build instructions do not even show C12 (C27 on the old photo):