The reason why Shlomo didnt use David Ha Melech's Gold and Silver was because
A- When The Beis Ha Mikdash will get destroyed Shlomo did not want the Non Jews to claim that there gods destroyed the Beis Ha Mikdash since it was from their nations gold and silver
B- Shlomo thought that David Ha Melech should have used the Gold and Silver to help the Jews who were starving, Instead of using the Gold and Silver for the Beis Ha mikdash
C- Hashem wanted Shlomo to build the Beis Ha mikdash himself.
D- The Beis Ha Mikdash was supposed to be the house of peace and the gold and silver were gained from wars.