There is no official copyright notice on this material -- is it still copyrighted?

Copyright holders are not required to label their work with an official copyright notice in order for the work to still be protected by copyright law. If the material in question was created after 1923, then it is copyrighted for 95 years after the date it was created. If you are not the author of the specific material you wish to upload, you MUST get express permission from the author.