I would say the answer is YES and NO. Why?
Mandarin Chinese does not have any verb conjugations as English to express tense. All verbs have a single form. How do we express tense in Chinese? There are couple strategies.
1, state the time, e.g. 昨天我加班。(I worked overtime yesterday.)
2, use “V+过” to express past experience. e.g. 我吃过北京烤鸭.（I have eaten Peking duck.）
3, using “V+ particle 了” to complete actions.
e.g. 你吃早饭了吗？--我吃了。(Did you have breakfast? –I ate.)
Thus, in this scenario, the particle 了 indicates that the action occurred in the past and has been completed. That’s why I said the answer is YES.
However, particle 了 also indicates other things, such as the happening of something, the emergence of a circumstance and the change of a situation. It is used at the tail of a sentence, indicating an affirmative.
Eg, 他跟家人去上海了。（He went to Shanghai with his family.）
孩子已经睡着了。( The baby fell asleep. He was awake.)
下雨了,我们回去吧。（It started raining, and let’s go home.）
我18岁了。(I turn to 18. I am not 17 anymore)
In addition, particle 了 indicates an act is about to take place. There are couple fixed phases to express this. Such as: 要…了/就要…了/ 快要…了/快…了
Eg, 1，她要走了。(She is going to leave.)
2，他就要大学毕业了。 （He is about to graduate from college. He is a senior）
（Christmas is coming. I want to buy some gifts for family. ）
4，你妈妈快来了，别着急。(Your mom is coming. Don’t worry. )
In these scenarios, none of them indicates past actions. On the contrary, they indicate actions occurring in the future. Therefor the answer is NO.
Hope the answer helps you guys have a better understanding of particle 了. Thanks.