China Overprint Stamps

hi there I got some stuff from a estate sale. and in one of the cases we bought I found some stamp wrapped up. really having trouble finding them and if they are real....any info would be wonderful

Hopefully very soon someone will help you with Scott numbers. Until that some informations from an old French catalogue:
1. Republic of China- stamp issued bw. 1923-1933, overprinted between 1925-1935 (so it`s China, the overprint means something like: `made for a limited time`) Everything seems OK, colour, overprint, it`s a low CV stamp.
2.Republic of China- stamp issued bw. 1943-1944, overprinted in 1945-1946
3..Republic of China- stamp issued bw.1931-1945, overprinted in 1945-1946.
4. ..Republic of China- stamp issued bw. 1943-1946, overprinted in 1948.

Last one: overprint in 1948. My old catalogue is divided this way: CHINA:
-EMPIRE (1878-1912)
-REPUBLIC (1912-1949)
- and from 1949 PEOPLE`S REPUBLIC OF CHINA.(CENTRAL, NORTH-CHINA etc.) So these stamps should be in any catalogue I guess under REPUBLIC OF CHINA, bw. 1925-1948. All seem OK to me, but I`m not collecting China (everything is, as shown in my catalogue: overprint, colour of the overprints, etc.)

thank you soooooo much for the info :)