Check this website out:
http://www.sightm1911.com/1911Production.htm
According to it, the Series 70 1911's didn't have a serial number in that format. I found no reference to "WCB" on that page.
Maybe if you took a good picture of it, showing the serinal number and other stampings, and posted it here someone could help you. Just in case there's some confusion as to reading the serial number and such.
Here's what that site had to say about the serial numbers for the 1911's of that time:
During 1970 the change to the new series “70″ begins and serial numbers changed also.
S/N 70G01001 to 70G05550 – 1970 – 4550
S/N 70G05551 to 70G18000 – 1971 – 12,450
S/N 70G18001 to 70G34400 – 1972 – 16,400
S/N 70G34401 to 70G43000 – 1973 – 8600
S/N 70G43001 to 70G73000 – 1974 – 30,000
S/N 70G73001 to 70G88900 – 1975 – 15,900
S/N 70G88901 to 70G99999 – 1976 – 11,099
During 1976 a range change of serial number begins.
S/N 01001G70 to 13900G70 – 1976 – 12,900
S/N 13901G70 to 45199G70 – 1977 – 31,299
S/N 45200G70 to 89185G70 – 1978 – 43,986
S/N 89186G70 to 99999G70 – 1979 – 10,813
During 1979 a range change of serial numbers begins on March 20, 1979.
S/N 01000B70 to 30008B70 – 1979 – 29,008
S/N 30009B70 to 72989B70 – 1980 – 42,981
S/N 72990B70 to 99999B70 – 1981 – 27,009
During 1981 a range change of serial numbers begins on Oct. 17, 1981.
S/N 70B00001 to 70B11246 – 1981 – 11,246
There are some really knowledgable guys on this site who will be able to help you, so hang in there.
EDIT
Just found out that "WCB" was part of the serial number for "Wiley Clapp Edition" Colt 1911's.
I'll do some digging for you on this, but it should help you some.
EDIT #2
Looks like uaarguy beat me to it with his post.