Is there a difference between Liu Ti and Ouyang Ti?

There are differences.

Liu Gongquan was the last great calligrapher in the Tang Dynasty and one of the four masters of regular script (Ou Yangxun, Yan Zhenqing, Liu Gongquan and Zhao Mengfu). His handwriting is even, thin and hard, and he pursues Wei Bei firmly. His stippling is crisp and beautiful, with thick bones and tight body. "Books are expensive, thin and hard, and the spirit is clear." Compared with his face, his regular script is slightly flat and thin, so it is called "Yan Gu". (see above)

European style is a regular script font created by Ou Yangxun, a great calligrapher in the Tang Dynasty. It is characterized by the combination of harmony, strong stippling and cohesive brushwork. It is steep and rigorous. Keep the side stable, compact and sparse. (see the picture below)