Were the first Atomic/Nuclear bombs (developed under the direction of
American physicist J. Robert Oppenheimer) designed using Standard
(English) measurements such as the inch or yard, or by Metric
measurements such as the centimeter or millimeter.

In addition to the answer, I require a reliable source or sources
(either physical or electronic) cited that I may view and demonstrate
to back the finding.  Locating as many sources on the internet as
practical will provide me with the most benefit since these sources,
while prone to fallacies, are the most easiest to demonstrate and as
long as there are many of them; I feel that proof can be made. 
However, physical references will work as well.

This question is asked to quell a minor dispute.  I attest that the
bombs were designed using Metric measurements (for logical reasons),
but another close individual maintains that they were designed using
English measurements.  I'd like to see which one of us is right.

Thank you in advance for taking the time to research this question.