Yes, it happens from time to time and is perfectly acceptable to do. Nevertheless, you should seek advice regarding the procedure from more experienced colleagues (and definitely from your supervisor) before attempting to contact the authors.
If the paper was published in the 80s, I very much doubt you'll get anywhere. While the PI might still be active and easy enough to track down, bear in mind that the experiment may have been done by a student in the lab. In any case, whoever did the experiment is unlikely to remember it in sufficient detail after 30 years to be of any more help than someone closer at hand.
If it was me, I wouldn't contact them.
You could explain what the reaction is and what you have tried here on the forums (and give a citation) and we can try to help you - that will probably be a far more productive use of your time.