Hi, I was not required to show them anything except for passport and yellow fever certificate. And this from VisaHQ's website:
"Following WHO guidelines issued in 1973, a cholera vaccination certificate is no longer a condition of entry to Angola. However, cholera is a serious risk in this country and precautions are essential. Up-to-date advice should be sought before deciding whether these precautions should include vaccination as medical opinion is divided over its effectiveness. For more information, consult the Health appendix."
Hope that helps!
"The fates lead him who will; him who won't they drag." - Anon