Yes, it’s ok to have more that 12 columns in a row It will just make the extra columns wrap to the next line. So, with your example you’d have 2 rows of 4.
From the Bootstrap docs (http://getbootstrap.com/css/#grid)..
“If more than 12 columns are placed within a single row, each group of
extra columns will, as one unit, wrap onto a new line”
Also, here are some examples that show using more than 12 columns (col-*) in a single row: http://getbootstrap.com/css/#grid-example-mixed
Just be aware of responsive resets if the columns vary in height.
Read more about when to use Bootstrap row
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