Hi , 
Are there any built-in scripts provided from the IBM side that can automatically upgrade MQ versions in Windows/Linux/AIX? In case there are more than 50 + servers which need patching, is there any way to automate it?

IBM used to have a product - BigFix or Endpoint Manager - that did automated deployment of OS and product updates including MQ. But that solution was sold off a few years ago. MQ doesn't have anything specific, as it is really a cross-product enterprise-wide requirement to have a single tool to handle the need. With all the controls, reporting, rollback options etc. Doing it "properly" is not a small job.

there is no OOB product, but using Ansible; you can achieve it.
There is an ansible module being built; does multiple things to automate. 

If u see something missing; then add module `command` or `shell` to achieve the automation.

We use it and have seen success. 
IBM is working to enhance the ansibel module; till then you would need some of your customization.