Yes. If someone using Outlook or Notes sends you a meeting invitation that includes an attachment, you'll get the attachment in the email invitation. However, the attachment won't appear in the event on your calendar.
FAQ Category: Cal-attach
Can I attach files to a meeting invitation?
Yes. Click the link to either attach a Google Doc or upload any other type of file from your computer or network (such as a Microsoft Office document, PDF, and so on). Note that you'll have to share any Google Doc you attach with guests for them to view the attachment.