For an abelian surface $A/\mathbb{Q}$ such that $R:=$End$_{\mathbb{Q}}(A)$$R:=\mathrm{End}_{\mathbb{Q}}(A)$ is an order in a real quadratic field $K$ (so a GL$_2$$\mathrm{GL}_2$-type surface), is there a bound on the index $[O_K : R]$ of the ring inside the maximal order $O_K$?