Yup, there were no template changes between 6.4.1 and 6.4.2 so it should work just fine
With the new features in Threads 6.5 you might want to consider paying for another year of support. 6.5 handles dead hyperlink removal by using a variable in the php scripts that places the display: none CSS property in the templates for dead hyperlinks (so they don't display). Future templates will be designed to use the display property, so any template that is designed for 6.5+ will definitely not work correctly for previous versions of Threads...