New Years - Open/Closed Conflicting

I will be in tokyo from the 29th of december til the 3rd Jan.

I would like to see the tsukiji Fish Market and tokyo national museum.

are they open on any these days.

i have checked the official website for both and they appear to be (open for at least one day over this period) however have seen other posts displaying they are not..

Any input would be appreciated. Any other advice during this time would be appreciated.

I expect that many of the places have not decided on or published their closing dates for 2012/2013 yet, but the pattern is always similar. Here are the closing dates for some major sites for last New Year:
http://www.japan-guide.com/e/e2276.html

[Tsukiji wholesale market]
Tuna auction area is closed when business is very busy;
it will highly likely be closed in Dec. 2012 and in early Jan. 2013.
Other areas (except off-limits) will be open until 30 Dec. 2012 and probably be closed from 31 Dec. 2012 through 4 Jan. 2013.
- http://www.japan-guide.com/e/e3021.html

[Tokyo National Museum]
- http://www.tnm.jp/modules/r_free_page/index.php?id=113&lang=en
Honkan and Heiseikan will be closed from 25 Dec. 2012 through 1 Jan. 2013.