Here too, things seem to be reversed, as one enters Shabbos first as it commences, and only afterwards exits from the sanctity of Shabbos at its conclusion. Many of the answers for this question will answer ours as well. However, upon the death of Moshe both these types of pillars ceased. Moshe died on Shabbos in the afternoon according to the opinion of many, hence the first time the bnei Yisroel were in doubt as to when the day ended was as Shabbos ended. Therefore there was an addition to the Shabbos at its end before there was an addition at its beginning the following Friday.
Gold is a prestigious item that when donated is proudly bantered about for all to see.
Silver is not. The Tur Shulchan Oruch O.Ch. 1 adds that although the completion of the creation of the Mishkon, its vessels, and the priestly garments took place on the 25th of Kisleiv, the actual assembly of the Mishkon took place on the first day of Nison, as mentioned in numerous medroshim. According to the above, even if the vessels were crafted after the creation of the Mishkon components, since the vessels were completed by the 25th of Kisleiv and the Mishkon was not assembled until the next Rosh Chodesh Nison, the vessels were completed and the Mishkon was not assembled, so there still wasn't a building into which the vessels could be placed. The Chasam Sofer in his responsa O.Ch.